Here below some basic MCQ’s about “Quantum Mechanical Model” with answer which is explained in details. Let’s check one by one which is given below.
MCQ 1
Which of the following statements about the quantum mechanical model of the atom is true?
A) Electrons move in fixed orbits around the nucleus.
B) The position and momentum of an electron can be known simultaneously with arbitrary precision.
C) Electrons exist in probabilistic orbitals, described by wave functions.
D) The energy of electrons is not quantized.
Answer: C) Electrons exist in probabilistic orbitals, described by wave functions.
Explanation: The quantum mechanical model introduces the concept of wave functions and probability distributions, meaning electrons do not have fixed orbits but exist in orbitals defined by probabilities. Options A and D are characteristic of the Bohr model, while B refers to the Heisenberg Uncertainty Principle, which states that position and momentum cannot both be precisely known at the same time.
MCQ 2
What does the principal quantum number (n) indicate in the quantum mechanical model of the atom?
A) Shape of the orbital
B) Orientation of the orbital
C) Size and energy of the orbital
D) Spin of the electron
Answer: C) Size and energy of the orbital.
Explanation: The principal quantum number (n) determines the energy level and size of an electron’s orbital. As n increases, the orbital’s energy and size increase. The shape of the orbital is indicated by the azimuthal quantum number (l), while orientation is specified by the magnetic quantum number (m_l), and spin is represented by the spin quantum number (m_s).
MCQ 3
The Schrödinger equation is fundamental to quantum mechanics because it:
A) Describes the motion of macroscopic objects.
B) Provides a way to calculate the energy levels of an electron in an atom.
C) Predicts the exact position of electrons.
D) Is used exclusively in chemical reactions.
Answer: B) Provides a way to calculate the energy levels of an electron in an atom.
Explanation: The Schrödinger equation is a key equation in quantum mechanics that describes how the quantum state of a physical system changes over time. It is used to calculate the allowed energy levels of electrons in atoms and to find the wave functions of particles. It does not predict exact positions (which is impossible due to the uncertainty principle) and is applicable in various areas of physics, not just chemical reactions.
MCQ 4
Which of the following correctly describes the concept of electron spin?
A) Electrons are stationary and do not spin.
B) Electron spin is a property that can take two values: +1/2 and -1/2.
C) Spin is related to the physical rotation of electrons around the nucleus.
D) Electrons spin in only one direction.
Answer: B) Electron spin is a property that can take two values: +1/2 and -1/2.
Explanation: Electron spin is a fundamental property of electrons, akin to angular momentum, and can be thought of as a form of intrinsic angular momentum. It does not refer to actual physical rotation but rather a quantum property. The values +1/2 and -1/2 represent the two possible spin states of an electron. Options A and C are incorrect, and option D is misleading since electrons can be in a superposition of spin states.
MCQ 5
What is the shape of an s orbital?
A) Dumbbell
B) Spherical
C) Double dumbbell
D) Linear
Answer: B) Spherical.
Explanation: An s orbital is spherical in shape, representing a region where there is a high probability of finding an electron. In contrast, p orbitals have a dumbbell shape, and d orbitals can be more complex.
MCQ 6
Which of the following quantum numbers describes the orientation of an orbital?
A) Principal quantum number (n)
B) Azimuthal quantum number (l)
C) Magnetic quantum number (m_l)
D) Spin quantum number (m_s)
Answer: C) Magnetic quantum number (m_l).
Explanation: The magnetic quantum number (m_l) specifies the orientation of an orbital in space. The principal quantum number (n) indicates the energy level, while the azimuthal quantum number (l) describes the shape, and the spin quantum number (m_s) refers to the electron’s spin.
MCQ 7
What does the Heisenberg Uncertainty Principle state?
A) Electrons move in definite paths.
B) The energy of an electron is always constant.
C) The position and momentum of a particle cannot both be precisely determined at the same time.
D) All particles have wave properties.
Answer: C) The position and momentum of a particle cannot both be precisely determined at the same time.
Explanation: The Heisenberg Uncertainty Principle highlights a fundamental limit to the precision with which pairs of physical properties, such as position and momentum, can be known simultaneously.
MCQ 8
Which of the following represents the maximum number of electrons that can occupy an orbital?
A) 1
B) 2
C) 6
D) 8
Answer: B) 2.
Explanation: Each orbital can hold a maximum of two electrons, and they must have opposite spins due to the Pauli Exclusion Principle.
MCQ 9
Which quantum number indicates the shape of an orbital?
A) Principal quantum number (n)
B) Azimuthal quantum number (l)
C) Magnetic quantum number (m_l)
D) Spin quantum number (m_s)
Answer: B) Azimuthal quantum number (l).
Explanation: The azimuthal quantum number (l) determines the shape of the orbital. For example, l = 0 corresponds to an s orbital, l = 1 to a p orbital, and l = 2 to a d orbital.
MCQ 10
What is the principle behind electron configurations in atoms?
A) Electrons fill orbitals in random order.
B) Electrons fill the lowest energy orbitals first (Aufbau principle).
C) All orbitals must be filled before any can be doubled up.
D) The total number of electrons in an atom is always equal to the atomic number.
Answer: B) Electrons fill the lowest energy orbitals first (Aufbau principle).
Explanation: The Aufbau principle states that electrons occupy the lowest energy orbitals available before moving to higher ones. This helps to determine the electron configuration of elements.
MCQ 11
Which of the following is NOT a consequence of the quantum mechanical model?
A) Electrons exhibit wave-particle duality.
B) The quantization of energy levels in atoms.
C) Electrons have definite paths around the nucleus.
D) The existence of orbitals.
Answer: C) Electrons have definite paths around the nucleus.
Explanation: In the quantum mechanical model, electrons do not have definite paths but exist in probabilistic orbitals. The model allows for wave-particle duality and quantized energy levels.
MCQ 12
What is the maximum number of electrons in a shell with principal quantum number n = 3?
A) 2
B) 8
C) 18
D) 32
Answer: C) 18.
MCQ 13
Which principle states that no two electrons in an atom can have the same set of quantum numbers?
A) Hund’s Rule
B) Aufbau Principle
C) Pauli Exclusion Principle
D) Heisenberg Uncertainty Principle
Answer: C) Pauli Exclusion Principle.
Explanation: The Pauli Exclusion Principle asserts that no two electrons in the same atom can have identical quantum numbers, ensuring that each electron occupies a unique state.
MCQ 14
Which of the following statements about the p orbitals is true?
A) They can hold a maximum of 2 electrons.
B) They are spherical in shape.
C) There are three p orbitals in each energy level starting from n = 2.
D) They exist only in the n = 1 shell.
Answer: C) There are three p orbitals in each energy level starting from n = 2.
Explanation: Each p subshell contains three orbitals, which can hold a total of 6 electrons. P orbitals are not spherical; they have a dumbbell shape and start appearing from the second energy level.
MCQ 15
Which of the following is a valid set of quantum numbers for an electron in a 3p orbital?
A) n = 3, l = 2, m_l = 0, m_s = +1/2
B) n = 3, l = 1, m_l = -1, m_s = -1/2
C) n = 2, l = 1, m_l = 1, m_s = +1/2
D) n = 1, l = 0, m_l = 1, m_s = -1/2
Answer: B) n = 3, l = 1, m_l = -1, m_s = -1/2.
Explanation: For a 3p orbital, the principal quantum number (n) is 3, the azimuthal quantum number (l) is 1 (for p orbitals), and the magnetic quantum number (m_l) can be -1, 0, or +1. The spin quantum number (m_s) can be +1/2 or -1/2.
MCQ 16
Which of the following describes the wave-particle duality of electrons?
A) Electrons can be in only one state at a time.
B) Electrons behave as both particles and waves.
C) Electrons do not exhibit any wave-like properties.
D) Electrons have a definite mass and charge.
Answer: B) Electrons behave as both particles and waves.
Explanation: Wave-particle duality is a fundamental concept in quantum mechanics, indicating that electrons exhibit properties of both particles and waves depending on the experiment.
MCQ 17
What does the term “degenerate orbitals” refer to?
A) Orbitals that are filled in the same energy level.
B) Orbitals that have the same energy level.
C) Orbitals that contain the same number of electrons.
D) Orbitals that have different shapes.
Answer: B) Orbitals that have the same energy level.
Explanation: Degenerate orbitals refer to orbitals that have the same energy, such as the three p orbitals in a given shell, which are equal in energy.
MCQ 18
In the hydrogen atom, what is the energy of an electron in the n = 1 level?
A) -13.6 eV
B) 0 eV
C) +13.6 eV
D) -1.51 eV
Answer: A) -13.6 eV.
Explanation: In the hydrogen atom, the energy of the electron in the n = 1 level is -13.6 eV. This negative value indicates that the electron is bound to the nucleus.
MCQ 19
According to Hund’s Rule, how should electrons be distributed in degenerate orbitals?
A) Pair up in the same orbital before filling others.
B) Fill each orbital singly before pairing.
C) Randomly fill orbitals.
D) Fill the lowest energy orbitals first.
Answer: B) Fill each orbital singly before pairing.
Explanation: Hund’s Rule states that electrons will occupy degenerate orbitals singly with parallel spins before any orbital is doubly occupied, maximizing total spin.
MCQ 20
Which of the following correctly describes the d orbitals?
A) They have a dumbbell shape.
B) There are five d orbitals in a d subshell.
C) They can hold a maximum of 6 electrons.
D) They appear in energy levels starting from n = 1.
Answer: B) There are five d orbitals in a d subshell.
Explanation: The d subshell contains five orbitals, and it can hold a maximum of 10 electrons. D orbitals have more complex shapes compared to s and p orbitals and start from the n = 3 level.
MCQ 21
What is the significance of the wave function (ψ) in quantum mechanics?
A) It determines the exact position of an electron.
B) It describes the probability distribution of an electron.
C) It represents the energy of an electron.
D) It is irrelevant to the behavior of electrons.
Answer: B) It describes the probability distribution of an electron.
Explanation: The wave function (ψ) provides information about the probability of finding an electron in a certain region of space, not its exact position.
MCQ 22
What happens to the energy levels of electrons as you move to higher principal quantum numbers?
A) They decrease.
B) They remain the same.
C) They increase.
D) They become negative.
Answer: C) They increase.
Explanation: As the principal quantum number (n) increases, the energy levels of electrons increase, indicating that the electrons are located farther from the nucleus.
MCQ 23
Which of the following statements about the photon is true?
A) It has mass.
B) It has a charge.
C) It exhibits both wave and particle characteristics.
D) It is always in a stationary state.
Answer: C) It exhibits both wave and particle characteristics.
Explanation: A photon is a quantum of electromagnetic radiation that behaves both as a wave and as a particle, demonstrating wave-particle duality.
MCQ 24
What is the electron configuration of oxygen (atomic number 8)?
A) 1s² 2s² 2p²
B) 1s² 2s² 2p⁴
C) 1s² 2s² 2p⁶
D) 1s² 2s² 2p³
Answer: B) 1s² 2s² 2p⁴.
Explanation: The electron configuration for oxygen, which has 8 electrons, fills the 1s and 2s orbitals first, followed by four electrons in the 2p orbitals.
MCQ 25
What is the term for the energy required to remove an electron from an atom in its gaseous state?
A) Electron affinity
B) Ionization energy
C) Electronegativity
D) Atomic radius
Answer: B) Ionization energy.
Explanation: Ionization energy is the energy required to remove an electron from an isolated atom in the gas phase, and it indicates how strongly an atom holds onto its electrons.
MCQ 26
Which of the following elements has the highest electronegativity?
A) Fluorine
B) Oxygen
C) Nitrogen
D) Carbon
Answer: A) Fluorine.
Explanation: Fluorine is the most electronegative element, meaning it has the highest tendency to attract electrons in a chemical bond.
MCQ 27
Which quantum number is not required for specifying an electron in a hydrogen atom?
A) Principal quantum number (n)
B) Azimuthal quantum number (l)
C) Magnetic quantum number (m_l)
D) Spin quantum number (m_s)
Answer: B) Azimuthal quantum number (l).
Explanation: In hydrogen, the energy levels depend only on the principal quantum number (n), so the azimuthal quantum number (l) does not influence the energy.
MCQ 28
What is the correct order of filling orbitals according to the Aufbau principle?
A) 1s, 2s, 2p, 3s, 3p, 4s, 3d
B) 1s, 2s, 2p, 3s, 3d, 4s
C) 1s, 2s, 3s, 3p, 4s, 3d
D) 1s, 2s, 3s, 3p, 4s, 4p
Answer: A) 1s, 2s, 2p, 3s, 3p, 4s, 3d.
Explanation: The correct filling order follows the Aufbau principle, which prioritizes the lowest energy levels first, including 4s before 3d.
MCQ 29
Which of the following is true about the ground state of an atom?
A) Electrons are in the highest energy state.
B) Electrons fill higher orbitals first.
C) Electrons occupy the lowest available energy levels.
D) All orbitals are half-filled.
Answer: C) Electrons occupy the lowest available energy levels.
Explanation: In the ground state, electrons are arranged in the lowest possible energy levels according to the Aufbau principle, maximizing stability.
MCQ 30
In which of the following configurations does the element exhibit paramagnetism?
A) 1s² 2s² 2p⁶
B) 1s² 2s² 2p⁴
C) 1s² 2s² 2p³
D) 1s² 2s² 2p²
Answer: C) 1s² 2s² 2p³.
Explanation: An element exhibits paramagnetism when it has unpaired electrons. Configuration C has three unpaired electrons in the 2p orbitals, making it paramagnetic.
MCQ 31
The energy of an electron in an atom is quantized. What does this mean?
A) Electrons can have any energy.
B) Electrons have discrete energy levels.
C) Electrons can exist in two states at once.
D) Electrons are stationary.
Answer: B) Electrons have discrete energy levels.
Explanation: Quantization of energy means that electrons can only exist in specific energy levels, rather than any value.
MCQ 32
Which of the following phenomena is explained by the wave nature of electrons?
A) Photoelectric effect
B) Atomic stability
C) Chemical bonding
D) Ionization energy
Answer: A) Photoelectric effect.
Explanation: The photoelectric effect demonstrates the wave-particle duality of light and is explained by considering light as a wave and a stream of photons.
MCQ 33
What is the correct electron configuration for sulfur (atomic number 16)?
A) 1s² 2s² 2p⁶ 3s² 3p⁴
B) 1s² 2s² 2p⁶ 3s² 3p³
C) 1s² 2s² 2p⁶ 3s² 3p²
D) 1s² 2s² 2p⁶ 3s² 4p²
Answer: A) 1s² 2s² 2p⁶ 3s² 3p⁴.
Explanation: Sulfur has 16 electrons, filling the orbitals up to 3p, which has four electrons.
MCQ 34
What occurs when an electron transitions from a higher energy level to a lower one?
A) Absorption of energy
B) Emission of energy
C) Ionization
D) Excitation
Answer: B) Emission of energy.
Explanation: When an electron drops from a higher energy level to a lower one, it emits energy in the form of a photon.
MCQ 35
The term “ionic bond” refers to:
A) A bond formed by the sharing of electrons.
B) A bond formed by the transfer of electrons.
C) A bond with a partial charge.
D) A covalent bond with multiple shared pairs.
Answer: B) A bond formed by the transfer of electrons.
Explanation: An ionic bond is formed when one atom donates an electron to another, resulting in attraction between positively and negatively charged ions.
MCQ 36
Which of the following is a characteristic of covalent bonds?
A) High melting and boiling points.
B) Formed by the transfer of electrons.
C) Typically soluble in water.
D) Involves sharing of electrons.
Answer: D) Involves sharing of electrons.
Explanation: Covalent bonds involve the sharing of electron pairs between atoms, leading to the formation of molecules.
MCQ 37
What is the shape of a molecule with a tetrahedral arrangement of electron pairs?
A) Linear
B) Trigonal planar
C) Tetrahedral
D) Bent
Answer: C) Tetrahedral.
Explanation: A tetrahedral arrangement occurs when four electron pairs (bonding or lone pairs) are arranged around a central atom, leading to a three-dimensional tetrahedral shape.
MCQ 38
What is the primary factor that determines the shape of a molecule?
A) The number of protons.
B) The type of bonds formed.
C) The arrangement of electron pairs around the central atom.
D) The size of the atoms involved.
Answer: C) The arrangement of electron pairs around the central atom.
Explanation: The VSEPR theory states that the shape of a molecule is determined by the repulsions between electron pairs, including bonding and lone pairs.
MCQ 39
In which type of bond are electrons shared equally?
A) Ionic bond
B) Polar covalent bond
C) Nonpolar covalent bond
D) Metallic bond
Answer: C) Nonpolar covalent bond.
Explanation: In a nonpolar covalent bond, electrons are shared equally between atoms, typically between identical atoms or those with similar electronegativities.
MCQ 40
What is the hybridization of a carbon atom in ethylene (C₂H₄)?
A) sp
B) sp²
C) sp³
D) sp³d
Answer: B) sp².
Explanation: In ethylene, each carbon atom is involved in a double bond with another carbon atom, leading to sp² hybridization, where one s and two p orbitals mix.
MCQ 41
Which of the following represents the octet rule?
A) Atoms lose or gain electrons to achieve a full outer shell of 8 electrons.
B) Atoms can have more than 8 electrons in their outer shell.
C) Only noble gases have full outer shells.
D) Electrons must always be paired in orbitals.
Answer: A) Atoms lose or gain electrons to achieve a full outer shell of 8 electrons.
Explanation: The octet rule states that atoms tend to gain, lose, or share electrons to achieve a full outer shell of eight electrons, promoting stability.
MCQ 42
Which type of reaction involves the breaking and forming of bonds to rearrange atoms?
A) Synthesis reaction
B) Decomposition reaction
C) Combustion reaction
D) Chemical reaction
Answer: D) Chemical reaction.
Explanation: A chemical reaction involves the breaking and forming of bonds, resulting in the rearrangement of atoms to form new substances.
MCQ 43
Which of the following elements is a noble gas?
A) Oxygen
B) Neon
C) Chlorine
D) Carbon
Answer: B) Neon.
Explanation: Noble gases, such as neon, are characterized by their complete outer electron shells and are generally nonreactive.
MCQ 44
What is the electron configuration of the alkali metal potassium (atomic number 19)?
A) 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹
B) 1s² 2s² 2p⁶ 3s² 3p⁶ 4p¹
C) 1s² 2s² 2p⁶ 3s² 3p⁵
D) 1s² 2s² 2p⁶ 3s² 3p³
Answer: A) 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹.
Explanation: Potassium has 19 electrons, with the outermost electron in the 4s orbital, characteristic of alkali metals.
MCQ 45
What is the primary type of intermolecular force in water (H₂O)?
A) Ionic bonding
B) Hydrogen bonding
C) Van der Waals forces
D) Metallic bonding
Answer: B) Hydrogen bonding.
Explanation: Water molecules exhibit hydrogen bonding due to the polarity of the molecule, leading to strong intermolecular attractions.
MCQ 46
Which of the following molecules has a linear shape?
A) H₂O
B) CO₂
C) CH₄
D) NH₃
Answer: B) CO₂.
Explanation: Carbon dioxide (CO₂) has a linear shape due to the arrangement of its double bonds, with a central carbon atom bonded to two oxygen atoms.
MCQ 47
What is the bond angle in a tetrahedral molecule?
A) 90°
B) 120°
C) 109.5°
D) 180°
Answer: C) 109.5°.
Explanation: In a tetrahedral arrangement, the bond angles are approximately 109.5°, resulting from the repulsion between four electron pairs.
MCQ 48
Which of the following best describes an exothermic reaction?
A) Heat is absorbed from the surroundings.
B) Heat is released to the surroundings.
C) There is no change in heat.
D) It occurs only in gases.
Answer: B) Heat is released to the surroundings.
Explanation: An exothermic reaction releases heat, resulting in an increase in temperature of the surroundings.
MCQ 49
Which type of bond involves the sharing of electron pairs between atoms?
A) Ionic bond
B) Covalent bond
C) Metallic bond
D) Hydrogen bond
Answer: B) Covalent bond.
Explanation: A covalent bond is formed when two atoms share one or more pairs of electrons, typically between nonmetals.
MCQ 50
Which molecule is an example of a polar covalent bond?
A) O₂
B) Cl₂
C) H₂O
D) N₂
Answer: C) H₂O.
Explanation: Water (H₂O) has a polar covalent bond due to the difference in electronegativity between hydrogen and oxygen, leading to a dipole moment.
MCQ 51
Which gas law relates pressure and volume at constant temperature?
A) Charles’s Law
B) Boyle’s Law
C) Avogadro’s Law
D) Ideal Gas Law
Answer: B) Boyle’s Law.
Explanation: Boyle’s Law states that at constant temperature, the pressure and volume of a gas are inversely related.
MCQ 52
What happens to the pressure of a gas if its volume is decreased while temperature remains constant?
A) Pressure decreases.
B) Pressure increases.
C) Pressure remains the same.
D) Pressure fluctuates.
Answer: B) Pressure increases.
Explanation: According to Boyle’s Law, decreasing the volume of a gas at constant temperature increases its pressure.
MCQ 53
Which of the following is a characteristic of an ideal gas?
A) Atoms attract each other.
B) Volume of the gas particles is significant.
C) Collisions between particles are elastic.
D) Gas particles have a definite shape.
Answer: C) Collisions between particles are elastic.
Explanation: In an ideal gas, collisions between gas particles are considered elastic, meaning there is no loss of kinetic energy during the collision.
MCQ 54
In which process does a solid change directly to a gas?
A) Melting
B) Sublimation
C) Condensation
D) Freezing
Answer: B) Sublimation.
Explanation: Sublimation is the process where a solid transforms directly into a gas without passing through the liquid phase.
MCQ 55
Which of the following is a characteristic of metals?
A) Brittle and non-conductive
B) Malleable and ductile
C) Gaseous at room temperature
D) Poor conductors of heat
Answer: B) Malleable and ductile.
Explanation: Metals are typically malleable (can be shaped) and ductile (can be drawn into wires) and are good conductors of heat and electricity.
MCQ 56
Which of the following is NOT a diatomic molecule?
A) H₂
B) O₂
C) N₂
D) CO₂
Answer: D) CO₂.
Explanation: Carbon dioxide (CO₂) is a linear molecule made up of one carbon atom and two oxygen atoms, making it a triatomic molecule, while H₂, O₂, and N₂ are diatomic.
MCQ 57
What type of reaction occurs when an acid and a base react to form water and a salt?
A) Synthesis
B) Decomposition
C) Neutralization
D) Combustion
Answer: C) Neutralization.
Explanation: A neutralization reaction occurs when an acid reacts with a base, resulting in the formation of water and a salt.
MCQ 58
What is the pH of a neutral solution at 25°C?
A) 0
B) 7
C) 14
D) 10
Answer: B) 7.
Explanation: A neutral solution has a pH of 7 at 25°C, indicating equal concentrations of hydrogen ions (H⁺) and hydroxide ions (OH⁻).
MCQ 59
Which of the following elements has the highest ionization energy?
A) Sodium
B) Magnesium
C) Chlorine
D) Argon
Answer: D) Argon.
Explanation: Argon, being a noble gas, has a full outer shell, making it more stable and requiring more energy to remove an electron compared to other elements.
MCQ 60
Which of the following statements about acids is true?
A) Acids have a pH greater than 7.
B) Acids turn blue litmus paper red.
C) Acids are always weak electrolytes.
D) Acids contain hydroxide ions.
Answer: B) Acids turn blue litmus paper red.
Explanation: Acids turn blue litmus paper red, indicating their acidic nature. They typically have a pH less than 7.
MCQ 61
Which of the following is a strong acid?
A) Acetic acid
B) Hydrochloric acid
C) Carbonic acid
D) Phosphoric acid
Answer: B) Hydrochloric acid.
MCQ 71
Which of the following processes involves the loss of electrons?
A) Reduction
B) Oxidation
C) Neutralization
D) Combustion
Answer: B) Oxidation.
Explanation: Oxidation is the process in which an atom, ion, or molecule loses electrons.
MCQ 72
In a redox reaction, the substance that is reduced is called the:
A) Reducing agent
B) Oxidizing agent
C) Reactant
D) Product
Answer: B) Oxidizing agent.
Explanation: The substance that gains electrons and is reduced is known as the oxidizing agent, as it facilitates the oxidation of another substance.
MCQ 73
Which of the following compounds is a strong electrolyte?
A) Sugar
B) Acetic acid
C) Sodium chloride
D) Ethanol
Answer: C) Sodium chloride.
Explanation: Sodium chloride (NaCl) completely dissociates into ions in solution, making it a strong electrolyte.
MCQ 74
Which of the following best describes a saturated solution?
A) Contains the maximum amount of solute at a given temperature.
B) Contains no solute.
C) Has a higher concentration of solute than the saturation point.
D) Contains an equal amount of solute and solvent.
Answer: A) Contains the maximum amount of solute at a given temperature.
Explanation: A saturated solution is one where no more solute can dissolve at a given temperature, meaning it has reached its saturation point.
MCQ 75
What type of bond is formed when electrons are transferred from one atom to another?
A) Covalent bond
B) Ionic bond
C) Metallic bond
D) Hydrogen bond
Answer: B) Ionic bond.
Explanation: An ionic bond is formed through the transfer of electrons, resulting in the attraction between positively and negatively charged ions.
MCQ 76
Which of the following is a characteristic of a covalent bond?
A) High melting and boiling points
B) Formation of anions and cations
C) Sharing of electron pairs
D) Conducts electricity in solution
Answer: C) Sharing of electron pairs.
Explanation: Covalent bonds involve the sharing of electron pairs between atoms, typically between nonmetals.
MCQ 77
What is the role of a catalyst in a chemical reaction?
A) Increases the activation energy
B) Decreases the rate of reaction
C) Lowers the activation energy
D) Is consumed in the reaction
Answer: C) Lowers the activation energy.
Explanation: A catalyst increases the rate of a chemical reaction by lowering the activation energy required for the reaction to occur.
MCQ 78
Which of the following is a property of a gas?
A) Has a definite shape
B) Has a definite volume
C) Expands to fill its container
D) Is incompressible
Answer: C) Expands to fill its container.
Explanation: Gases have no definite shape or volume and will expand to occupy the entire volume of their container.
MCQ 79
Which of the following statements is true about exothermic reactions?
A) They absorb heat from the surroundings.
B) They release heat to the surroundings.
C) They always produce gas.
D) They are endothermic.
Answer: B) They release heat to the surroundings.
Explanation: Exothermic reactions release heat, resulting in an increase in temperature of the surroundings.
MCQ 80
What type of bond forms between two metals?
A) Ionic bond
B) Covalent bond
C) Metallic bond
D) Hydrogen bond
Answer: C) Metallic bond.
Explanation: Metallic bonds occur between metal atoms, characterized by a “sea of electrons” that allows for conductivity and malleability.
MCQ 81
Which of the following is an example of a chemical change?
A) Ice melting
B) Dissolving salt in water
C) Burning wood
D) Boiling water
Answer: C) Burning wood.
Explanation: Burning wood is a chemical change as it produces new substances (ash, smoke) and involves a chemical reaction with oxygen.
MCQ 82
Which type of radiation has the highest penetrating power?
A) Alpha particles
B) Beta particles
C) Gamma rays
D) Ultraviolet rays
Answer: C) Gamma rays.
Explanation: Gamma rays have the highest penetrating power and can pass through most materials, requiring dense substances like lead for shielding.
MCQ 83
What is the main feature of a base?
A) Produces hydrogen ions in solution
B) Produces hydroxide ions in solution
C) Tastes sour
D) Turns blue litmus paper red
Answer: B) Produces hydroxide ions in solution.
Explanation: Bases produce hydroxide ions (OH⁻) in solution, which is a key characteristic of basic substances.
MCQ 84
What happens to the volume of a gas when its temperature increases at constant pressure?
A) Volume decreases.
B) Volume remains the same.
C) Volume increases.
D) Volume fluctuates.
Answer: C) Volume increases.
Explanation: According to Charles’s Law, at constant pressure, the volume of a gas increases as the temperature increases.
MCQ 85
Which of the following best defines a mole?
A) A measure of mass.
B) A measure of volume.
C) A unit of quantity representing 6.022 × 10²³ particles.
D) A measure of energy.
Answer: C) A unit of quantity representing 6.022 × 10²³ particles.
Explanation: A mole is defined as the amount of substance that contains the same number of entities (atoms, molecules, etc.) as there are in 12 grams of carbon-12.
MCQ 86
Which of the following is true about a chemical equilibrium?
A) The concentrations of reactants and products remain constant.
B) The reaction has stopped completely.
C) The forward reaction occurs faster than the reverse reaction.
D) There is no energy exchange.
Answer: A) The concentrations of reactants and products remain constant.
Explanation: In chemical equilibrium, the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products.
MCQ 87
What does the term “solubility” refer to?
A) The amount of solute that can be dissolved in a given amount of solvent at a specific temperature.
B) The ability of a solute to conduct electricity.
C) The measure of pH in a solution.
D) The speed of dissolution.
Answer: A) The amount of solute that can be dissolved in a given amount of solvent at a specific temperature.
Explanation: Solubility is a quantitative measure of how much solute can dissolve in a specific quantity of solvent at a given temperature.
MCQ 88
What is the primary product of the electrolysis of water?
A) Oxygen gas
B) Hydrogen gas
C) Ozone
D) Hydrogen peroxide
Answer: B) Hydrogen gas.
Explanation: The electrolysis of water primarily produces hydrogen gas at the cathode and oxygen gas at the anode.
MCQ 89
Which of the following processes increases the concentration of a solution?
A) Dilution
B) Evaporation
C) Filtration
D) Distillation
Answer: B) Evaporation.
Explanation: Evaporation removes solvent from a solution, thereby increasing the concentration of solute remaining.
MCQ 90
What is the effect of increasing the concentration of reactants on the rate of a chemical reaction?
A) Rate decreases.
B) Rate increases.
C) No effect.
D) Rate becomes constant.
Answer: B) Rate increases.
Explanation: Increasing the concentration of reactants generally increases the rate of reaction due to a higher probability of collisions between reactant molecules.
MCQ 91
Which of the following best describes a hydrocarbon?
A) A compound containing hydrogen and oxygen.
B) A compound containing only carbon and hydrogen.
C) A compound containing carbon, hydrogen, and nitrogen.
D) A compound containing carbon and sulfur.
Answer: B) A compound containing only carbon and hydrogen.
Explanation: Hydrocarbons are organic compounds made solely of hydrogen and carbon atoms.
MCQ 92
Which of the following is a characteristic of an endothermic reaction?
A) Releases heat.
B) Absorbs heat.
C) Produces gas only.
D) Occurs spontaneously.
Answer: B) Absorbs heat.
Explanation: Endothermic reactions absorb heat from their surroundings, resulting in a decrease in temperature.
MCQ 93
What type of bond is formed between sodium (Na) and chlorine (Cl) in sodium chloride (NaCl)?
A) Covalent bond
B) Ionic bond
C) Metallic bond
D) Hydrogen bond
Answer: B) Ionic bond.
Explanation: Sodium chloride (NaCl) is formed by the ionic bond resulting from the transfer of an electron from sodium to chlorine.
MCQ 94
Which of the following statements is true regarding the energy levels of an atom?
A) Energy levels are continuous.
B) Energy levels can only hold one electron.
C) Electrons in lower energy levels are more stable.
D) Energy levels have no influence on the atom’s chemical properties.
Answer: C) Electrons in lower energy levels are more stable.
Explanation: Electrons in lower energy levels are generally more stable due to being closer to the nucleus, where the attractive force is stronger.
MCQ 95
What is the shape of the p orbital?
A) Spherical
B) Dumbbell
C) Complex
D) Circular
Answer: B) Dumbbell.
Explanation: The p orbital has a characteristic dumbbell shape with two lobes.
MCQ 96
What is the term for the energy required to remove an electron from an atom?
A) Electron affinity
B) Ionization energy
C) Electronegativity
D) Activation energy
Answer: B) Ionization energy.
Explanation: Ionization energy is the energy needed to remove an electron from a gaseous atom or ion.
MCQ 97
What phenomenon is observed when light is passed through a prism?
A) Reflection
B) Diffraction
C) Dispersion
D) Absorption
Answer: C) Dispersion.
Explanation: Dispersion occurs when different wavelengths of light are separated as they pass through a prism, creating a spectrum.
MCQ 98
Which of the following is a consequence of the wave nature of electrons?
A) They have a definite position.
B) They exhibit interference patterns.
C) They can only exist in one energy state.
D) They do not interact with electromagnetic fields.
Answer: B) They exhibit interference patterns.
Explanation: The wave nature of electrons allows them to exhibit interference patterns, similar to light waves.
MCQ 99
What does the term “orbital” refer to in quantum chemistry?
A) A fixed path around the nucleus
B) A region of space where an electron is likely to be found
C) A particle with mass
D) An energy level of an atom
Answer: B) A region of space where an electron is likely to be found.
Explanation: An orbital describes the spatial distribution of an electron’s probability density around the nucleus.
MCQ 100
Which of the following elements has the largest atomic radius?
A) Helium (He)
B) Lithium (Li)
C) Sodium (Na)
D) Potassium (K)
Answer: D) Potassium (K).
Explanation: Atomic radius increases down a group in the periodic table due to the addition of electron shells, making potassium the largest among these elements.
MCQ 101
What does the principal quantum number (n) indicate?
A) Shape of the orbital
B) Size and energy level of the orbital
C) Orientation of the orbital
D) Spin of the electron
Answer: B) Size and energy level of the orbital.
Explanation: The principal quantum number (n) indicates the main energy level or shell in which an electron resides, reflecting the size and energy of the orbital.
MCQ 102
Which of the following quantum numbers describes the shape of an orbital?
A) Principal quantum number (n)
B) Azimuthal quantum number (l)
C) Magnetic quantum number (mₗ)
D) Spin quantum number (s)
Answer: B) Azimuthal quantum number (l).
Explanation: The azimuthal quantum number (l) determines the shape of the orbital, with values corresponding to different types of orbitals (s, p, d, f).
MCQ 103
Which of the following orbitals can hold a maximum of 10 electrons?
A) s orbital
B) p orbital
C) d orbital
D) f orbital
Answer: C) d orbital.
Explanation: The d orbital can hold a maximum of 10 electrons since it consists of 5 sub-orbitals, each capable of holding 2 electrons.
MCQ 104
Which quantum number describes the orientation of an orbital?
A) Principal quantum number (n)
B) Azimuthal quantum number (l)
C) Magnetic quantum number (mₗ)
D) Spin quantum number (s)
Answer: C) Magnetic quantum number (mₗ).
Explanation: The magnetic quantum number (mₗ) specifies the orientation of the orbital in space.
MCQ 105
What is the maximum number of electrons that can occupy the second energy level (n=2)?
A) 2
B) 8
C) 18
D) 32
Answer: B) 8.
MCQ 106
In which of the following does the electron occupy the highest energy state?
A) 1s
B) 2p
C) 3s
D) 3d
Answer: D) 3d.
Explanation: Among the given options, the 3d orbital has the highest energy state due to its location in the third shell.
MCQ 107
Which of the following describes the Pauli Exclusion Principle?
A) No two electrons can have the same set of four quantum numbers.
B) Electrons fill orbitals starting from the lowest energy level first.
C) Electrons in the same orbital must have opposite spins.
D) Both A and C.
Answer: D) Both A and C.
Explanation: The Pauli Exclusion Principle states that no two electrons in an atom can have the same set of four quantum numbers, and if two electrons are in the same orbital, they must have opposite spins.
MCQ 108
What does Hund’s Rule state?
A) Electrons occupy orbitals of the same energy singly before pairing up.
B) Electrons will fill lower energy orbitals before higher energy orbitals.
C) No two electrons can have the same set of quantum numbers.
D) The energy of an electron is quantized.
Answer: A) Electrons occupy orbitals of the same energy singly before pairing up.
Explanation: Hund’s Rule emphasizes that electrons will first fill degenerate orbitals (orbitals of the same energy) singly and only pair up when necessary.
MCQ 109
What is the electron configuration of a neutral nitrogen atom (atomic number 7)?
A) 1s² 2s² 2p¹
B) 1s² 2s² 2p³
C) 1s² 2s¹ 2p⁶
D) 1s² 2p⁵
Answer: B) 1s² 2s² 2p³.
Explanation: Nitrogen has 7 electrons, which are arranged in the electron configuration 1s² 2s² 2p³.
MCQ 110
Which of the following statements about the quantum mechanical model of the atom is true?
A) Electrons follow fixed orbits like planets around the sun.
B) The position of an electron can be precisely determined.
C) Electrons are found in probabilistic regions called orbitals.
D) The atom is primarily composed of solid matter.
Answer: C) Electrons are found in probabilistic regions called orbitals.
Explanation: The quantum mechanical model describes electrons as existing in probabilistic orbitals rather than fixed paths.
MCQ 111
What is the shape of the s orbital?
A) Dumbbell-shaped
B) Spherical
C) Double dumbbell
D) Linear
Answer: B) Spherical.
Explanation: The s orbital has a spherical shape, with the probability density of finding an electron uniformly distributed around the nucleus.
MCQ 112
What is the primary characteristic of a p orbital?
A) It is spherical in shape.
B) It can hold a maximum of 2 electrons.
C) It has a dumbbell shape.
D) It has no angular momentum.
Answer: C) It has a dumbbell shape.
Explanation: The p orbital is characterized by its dumbbell shape and can hold a maximum of 6 electrons across its three orientations.
MCQ 113
Which of the following statements about the d orbital is correct?
A) There are three d orbitals in a given energy level.
B) The d orbital is always higher in energy than the p orbital in the same principal energy level.
C) There are five d orbitals in a given energy level.
D) The d orbital can hold a maximum of 4 electrons.
Answer: C) There are five d orbitals in a given energy level.
Explanation: The d subshell consists of five orbitals, allowing it to hold a maximum of 10 electrons.
MCQ 114
What phenomenon describes the energy levels of electrons in an atom?
A) Electromagnetic radiation
B) Quantum mechanics
C) Classical mechanics
D) Thermodynamics
Answer: B) Quantum mechanics.
Explanation: Quantum mechanics explains the behavior of electrons and the quantized energy levels in atoms.
MCQ 115
Which of the following is true about electromagnetic radiation?
A) It travels at the speed of sound.
B) It consists of particles known as electrons.
C) It exhibits both wave-like and particle-like properties.
D) It cannot be quantified.
Answer: C) It exhibits both wave-like and particle-like properties.
Explanation: Electromagnetic radiation displays dual characteristics, behaving as both waves and particles (photons).
MCQ 116
Which quantum number cannot be negative?
A) Azimuthal quantum number (l)
B) Principal quantum number (n)
C) Magnetic quantum number (mₗ)
D) Spin quantum number (s)
Answer: B) Principal quantum number (n).
Explanation: The principal quantum number (n) is always a positive integer (1, 2, 3, …).
MCQ 117
What does the term “photoelectric effect” refer to?
A) The emission of electrons when light hits a material.
B) The absorption of light by an electron.
C) The generation of heat from light.
D) The reflection of light off a surface.
Answer: A) The emission of electrons when light hits a material.
Explanation: The photoelectric effect is the phenomenon where electrons are emitted from a material when it is exposed to light of sufficient energy.
MCQ 118
What is the uncertainty principle formulated by Heisenberg?
A) It states that the position and momentum of an electron can be precisely known.
B) It states that the energy of a system is always conserved.
C) It states that the position and momentum of an electron cannot be simultaneously measured with absolute precision.
D) It states that electrons exist in fixed orbits.
Answer: C) It states that the position and momentum of an electron cannot be simultaneously measured with absolute precision.
Explanation: Heisenberg’s uncertainty principle highlights the fundamental limit in measuring both the position and momentum of a particle at the same time.
MCQ 119
Which principle explains why electrons fill orbitals from lowest to highest energy?
A) Hund’s Rule
B) Pauli Exclusion Principle
C) Aufbau Principle
D) Dalton’s Law
Answer: C) Aufbau Principle
MCQ 120
In which of the following transitions does an electron absorb energy?
A) n=3 to n=2
B) n=2 to n=3
C) n=1 to n=2
D) Both B and C
Answer: D) Both B and C.
Explanation: Electrons absorb energy when moving from a lower energy level (n=2 or n=1) to a higher one (n=3).
MCQ 121
Which of the following describes the wave function in quantum mechanics?
A) It provides the exact position of an electron.
B) It gives the probability of finding an electron in a certain region.
C) It determines the mass of an electron.
D) It describes the speed of an electron.
Answer: B) It gives the probability of finding an electron in a certain region.
Explanation: The wave function, often represented as Ψ, provides the probability density of finding an electron in a specific region of space.
MCQ 122
Which of the following particles is not considered a fermion?
A) Electron
B) Proton
C) Photon
D) Neutron
Answer: C) Photon.
Explanation: Photons are bosons, not fermions, as they do not obey the Pauli Exclusion Principle.
MCQ 123
What is the primary difference between classical mechanics and quantum mechanics?
A) Classical mechanics deals with macroscopic objects, while quantum mechanics deals with microscopic particles.
B) Classical mechanics does not include wave-particle duality.
C) Quantum mechanics cannot explain everyday phenomena.
D) All of the above.
Answer: D) All of the above.
Explanation: Classical mechanics applies to macroscopic objects, while quantum mechanics addresses the behavior of microscopic particles, including wave-particle duality.
MCQ 124
What is the significance of the principal quantum number (n)?
A) It defines the shape of the orbital.
B) It indicates the size and energy level of the orbital.
C) It describes the orientation of the orbital.
D) It identifies the spin direction of an electron.
Answer: B) It indicates the size and energy level of the orbital.
Explanation: The principal quantum number (n) represents the main energy level and size of the orbital, with higher values indicating greater energy and distance from the nucleus.
MCQ 125
Which of the following quantum numbers can have negative values?
A) Principal quantum number (n)
B) Azimuthal quantum number (l)
C) Magnetic quantum number (mₗ)
D) Spin quantum number (s)
Answer: C) Magnetic quantum number (mₗ).
MCQ 126
What is the relationship between frequency and wavelength?
A) Directly proportional
B) Inversely proportional
C) Independent
D) None of the above
Answer: B) Inversely proportional.
Explanation: Frequency and wavelength are inversely related; as the frequency increases, the wavelength decreases, according to the formula
c=λν.
MCQ 127
Which of the following describes the quantum state of an electron?
A) Position and momentum
B) Only energy level
C) Probability distribution
D) Both A and C
Answer: D) Both A and C.
Explanation: The quantum state of an electron includes both its probability distribution and can describe aspects such as its position and momentum.
MCQ 128
What does the term “quantization” refer to in quantum mechanics?
A) The continuous range of energy levels
B) The existence of discrete energy levels
C) The measurement of energy
D) The wave-like behavior of particles
Answer: B) The existence of discrete energy levels.
Explanation: Quantization refers to the concept that energy levels in an atom are not continuous but exist in discrete amounts.
MCQ 129
In a hydrogen atom, which transition results in the emission of the longest wavelength photon?
A) n=3 to n=2
B) n=2 to n=1
C) n=4 to n=3
D) n=5 to n=4
Answer: D) n=5 to n=4.
Explanation: The transition with the smallest energy difference corresponds to the longest wavelength, which occurs when an electron falls from n=5 to n=4.
MCQ 130
Which of the following is a characteristic of an ionic bond?
A) Formed between nonmetals
B) Involves sharing of electrons
C) Generally has high melting and boiling points
D) Does not conduct electricity in solid state
Answer: C) Generally has high melting and boiling points.
Explanation: Ionic bonds typically result in compounds with high melting and boiling points due to strong electrostatic forces between the ions.
MCQ 131
Which of the following particles has no charge?
A) Proton
B) Neutron
C) Electron
D) Positron
Answer: B) Neutron.
Explanation: Neutrons are neutral particles found in the nucleus of an atom and do not carry any charge.
MCQ 132
What type of electromagnetic radiation has the shortest wavelength?
A) Infrared
B) Ultraviolet
C) X-rays
D) Gamma rays
Answer: D) Gamma rays.
Explanation: Gamma rays have the shortest wavelength and the highest energy of all types of electromagnetic radiation.
MCQ 133
Which quantum number is associated with the orientation of the electron’s spin?
A) Principal quantum number (n)
B) Azimuthal quantum number (l)
C) Magnetic quantum number (mₗ)
D) Spin quantum number (s)
Answer: D) Spin quantum number (s).
Explanation: The spin quantum number (s) indicates the direction of the intrinsic spin of an electron, which can be either +1/2 or -1/2.
MCQ 134
What is the main limitation of the Bohr model of the atom?
A) It only applies to hydrogen.
B) It cannot explain the spectra of multi-electron atoms.
C) It assumes electrons travel in fixed orbits.
D) All of the above.
Answer: D) All of the above.
Explanation: The Bohr model is limited as it is only applicable to hydrogen, cannot explain multi-electron spectra, and assumes fixed orbits for electrons.
MCQ 135
What is the fundamental principle of quantum superposition?
A) A particle can only exist in one state at a time.
B) A particle can exist in multiple states simultaneously.
C) A particle’s position can be precisely determined.
D) A particle’s energy is quantized.
Answer: B) A particle can exist in multiple states simultaneously.
Explanation: Quantum superposition states that a quantum system can exist in multiple states at once until it is measured.
MCQ 136
Which of the following is true about the Heisenberg Uncertainty Principle?
A) It allows precise measurement of both position and momentum.
B) It limits the accuracy of simultaneously measuring position and momentum.
C) It applies only to macroscopic objects.
D) It is a result of classical physics.
Answer: B) It limits the accuracy of simultaneously measuring position and momentum.
Explanation: The Heisenberg Uncertainty Principle highlights the inherent limitations in measuring certain pairs of physical properties simultaneously.
MCQ 137
What is the term used for the probability density of finding an electron in an atom?
A) Wave function
B) Quantum state
C) Orbit
D) Orbital
Answer: A) Wave function.
Explanation: The wave function provides the probability density for the location of an electron within an atom.
MCQ 138
Which particle is responsible for the chemical behavior of an atom?
A) Neutron
B) Proton
C) Electron
D) Nucleus
Answer: C) Electron.
Explanation: Electrons, especially those in the outermost shell, determine the chemical reactivity and bonding behavior of an atom.
MCQ 139
What type of orbitals are filled after the 4s orbital in the Aufbau principle?
A) 3d
B) 4p
C) 4d
D) 5s
Answer: A) 3d.
Explanation: According to the Aufbau principle, the 3d orbitals are filled after the 4s orbital due to their energy levels.
MCQ 140
Which of the following is a result of the wave-particle duality of matter?
A) Electrons have fixed positions.
B) Light behaves only as a wave.
C) Electrons can exhibit both particle and wave characteristics.
D) Atoms have a solid structure.
Answer: C) Electrons can exhibit both particle and wave characteristics.
Explanation: Wave-particle duality means that electrons can behave as both particles and waves, depending on the experimental conditions.
MCQ 141
Which principle states that two electrons in the same orbital must have opposite spins?
A) Aufbau Principle
B) Hund’s Rule
C) Pauli Exclusion Principle
D) Heisenberg Uncertainty Principle
Answer: C) Pauli Exclusion Principle.
Explanation: The Pauli Exclusion Principle states that no two electrons in an atom can have the same set of four quantum numbers, which includes having opposite spins in the same orbital.
MCQ 142
In quantum mechanics, what does the term “degenerate orbitals” refer to?
A) Orbitals with different shapes
B) Orbitals with the same energy level
C) Orbitals that can hold more than two electrons
D) Orbitals in different principal energy levels
Answer: B) Orbitals with the same energy level.
Explanation: Degenerate orbitals are orbitals that have the same energy, such as the three p orbitals in a given energy level.
MCQ 143
Which of the following correctly describes a photon?
A) A charged particle
B) A wave with mass
C) A massless particle of light
D) A particle with negative charge
Answer: C) A massless particle of light.
Explanation: A photon is a fundamental particle of light that has no mass and carries energy.
MCQ 144
Which of the following statements about wave functions is true?
A) They can be directly observed.
B) They must always be positive.
C) They can have both positive and negative values.
D) They do not relate to the probability of finding an electron.
Answer: C) They can have both positive and negative values.
Explanation: Wave functions can take on both positive and negative values, but their square gives the probability density.
MCQ 145
What happens to the energy of an electron as it moves from a higher energy level to a lower one?
A) Energy is absorbed.
B) Energy is released.
C) Energy remains the same.
D) Energy is lost as heat.
Answer: B) Energy is released.
Explanation: When an electron transitions from a higher energy level to a lower one, it releases energy, often in the form of a photon.
MCQ 146
What does the term “quantum leap” refer to in quantum mechanics?
A) The movement of an electron to a higher energy level.
B) The oscillation of a wave function.
C) The energy required to ionize an atom.
D) The uncertainty in measuring a particle’s position.
Answer: A) The movement of an electron to a higher energy level.
Explanation: A quantum leap refers to the transition of an electron between energy levels in an atom.
MCQ 148
What is the shape of the f orbital?
A) Spherical
B) Dumbbell-shaped
C) Complex with multiple lobes
D) Linear
Answer: C) Complex with multiple lobes.
Explanation: The f orbital has a complex shape with multiple lobes and is typically more complicated than s and p orbitals.
MCQ 149
Which of the following is a characteristic of metals in terms of their electron configuration?
A) They have high electronegativity.
B) They tend to lose electrons easily.
C) They have full outer shells.
D) They form anions.
Answer: B) They tend to lose electrons easily.
Explanation: Metals typically have few electrons in their outer shell and readily lose them to form cations.
MCQ 150
What is the principle behind the Schrödinger equation?
A) It describes the behavior of macroscopic objects.
B) It accounts for the wave-like nature of particles.
C) It defines the position of particles with certainty.
D) It is used only for hydrogen-like atoms.
Answer: B) It accounts for the wave-like nature of particles.
Explanation: The Schrödinger equation is fundamental in quantum mechanics and describes how the quantum state of a physical system changes over time, accounting for wave-like behavior.
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