Here below some basic MCQ’s about “Trends in periodic properties” which is explained in details. Let’s check one by one which is given below.
- Which of the following elements has the highest first ionization energy?
a) Sodium (Na)
b) Magnesium (Mg)
c) Aluminum (Al)
d) Phosphorus (P)
Answer: d) Phosphorus (P)
Explanation: Ionization energy generally increases across a period due to the increasing effective nuclear charge, which makes it harder to remove an electron. Phosphorus lies farthest to the right in this group, hence has a higher ionization energy than Na, Mg, and Al. Also, due to half-filled p-orbital stability, phosphorus has a higher ionization energy than aluminum.
- Which of the following elements has the largest atomic radius?
a) Carbon (C)
b) Nitrogen (N)
c) Oxygen (O)
d) Fluorine (F)
Answer: a) Carbon (C)
Explanation: Atomic radius decreases across a period from left to right due to increasing effective nuclear charge. Carbon, being the leftmost element in this group, has the largest atomic radius among these elements.
- In which period of the periodic table is the element with the electronic configuration [Ar] 3d¹⁰ 4s² 4p⁵ located?
a) Period 3
b) Period 4
c) Period 5
d) Period 6
Answer: b) Period 4
Explanation: The element has the outer electronic configuration 4s² 4p⁵, indicating that the last electron enters the 4th energy level. This places the element in period 4. The element is bromine (Br).
- Which of the following oxides is most acidic?
a) Na₂O
b) Al₂O₃
c) SiO₂
d) SO₃
Answer: d) SO₃
Explanation: Acidity of oxides increases across a period and decreases down a group. Non-metal oxides (like SO₃) tend to be more acidic, while metal oxides (like Na₂O) are basic. SO₃, being a non-metal oxide, is highly acidic.
- Which property decreases down the group in alkali metals?
a) Atomic radius
b) Ionization energy
c) Metallic character
d) Electronegativity
Answer: d) Electronegativity
Explanation: As we move down the group in alkali metals, atomic size increases, leading to decreased attraction for electrons, hence decreasing electronegativity. Ionization energy also decreases, but metallic character increases down the group.
- Which of the following elements has the smallest electron affinity?
a) Fluorine (F)
b) Chlorine (Cl)
c) Oxygen (O)
d) Sulfur (S)
Answer: a) Fluorine (F)
Explanation: While fluorine is expected to have high electron affinity, it is actually lower than chlorine’s. This is due to the small size of fluorine, which causes electron-electron repulsion when an extra electron is added, lowering its electron affinity.
- The ability of an atom in a molecule to attract shared electrons towards itself is called:
a) Ionization energy
b) Electron affinity
c) Electronegativity
d) Metallic character
Answer: c) Electronegativity
Explanation: Electronegativity is a measure of an atom’s ability to attract bonding electrons in a molecule. It differs from ionization energy and electron affinity, which refer to individual atoms in different contexts.
- Which of the following elements shows diagonal relationship with Lithium?
a) Sodium
b) Magnesium
c) Potassium
d) Beryllium
Answer: d) Beryllium
Explanation: Lithium and beryllium show a diagonal relationship due to similarities in their properties such as atomic and ionic sizes, electronegativity, and polarization power, despite being in different groups.
- Which of the following elements has the highest electronegativity?
a) Oxygen (O)
b) Nitrogen (N)
c) Fluorine (F)
d) Chlorine (Cl)
Answer: c) Fluorine (F)
Explanation: Fluorine is the most electronegative element in the periodic table. It has a strong ability to attract electrons towards itself in a chemical bond due to its small size and high effective nuclear charge.
- Which of the following statements is incorrect about the trends in the periodic table?
a) Electronegativity decreases down a group.
b) Atomic radius increases down a group.
c) Ionization energy increases across a period.
d) Metallic character increases across a period.
Answer: d) Metallic character increases across a period
Explanation: Metallic character decreases across a period from left to right due to increasing ionization energy and electronegativity, making elements less likely to lose electrons and form positive ions.
- Which of the following halogens has the weakest bond dissociation energy?
a) Fluorine (F₂)
b) Chlorine (Cl₂)
c) Bromine (Br₂)
d) Iodine (I₂)
Answer: a) Fluorine (F₂)
Explanation: Even though fluorine is the smallest and most electronegative halogen, the bond dissociation energy of F₂ is lower than Cl₂ because of the strong electron-electron repulsion in the small F-F bond. As a result, the bond is easier to break compared to chlorine.
- Which of the following has the highest electron affinity?
a) Fluorine (F)
b) Oxygen (O)
c) Chlorine (Cl)
d) Bromine (Br)
Answer: c) Chlorine (Cl)
Explanation: Although fluorine is more electronegative, chlorine has the highest electron affinity. This is because chlorine’s larger size leads to less electron repulsion when an electron is added compared to fluorine, making chlorine more favorable for accepting electrons.
- Which of the following elements is the most metallic?
a) Lithium (Li)
b) Sodium (Na)
c) Potassium (K)
d) Cesium (Cs)
Answer: d) Cesium (Cs)
Explanation: Metallic character increases down the group, so cesium, being the heaviest alkali metal, is the most metallic. Metallic character is related to the ability of an element to lose electrons and form positive ions, which increases as atomic size increases down the group.
- Which of the following trends is observed in the ionization energies of alkali metals?
a) Increases down the group
b) Decreases down the group
c) Remains constant down the group
d) Shows no clear pattern
Answer: b) Decreases down the group
Explanation: As we move down the group in alkali metals, the atomic size increases, which results in a decreased attraction between the nucleus and the outermost electron. Therefore, less energy is required to remove the outermost electron, leading to a decrease in ionization energy.
- Which group in the periodic table contains elements that are all gases at room temperature?
a) Group 1
b) Group 17
c) Group 18
d) Group 2
Answer: c) Group 18
Explanation: Group 18 elements are noble gases, which are all gases at room temperature. These include helium, neon, argon, krypton, xenon, and radon. Their stability is due to their complete outer electron shells, making them chemically inert.
- Which of the following elements has the highest second ionization energy?
a) Sodium (Na)
b) Magnesium (Mg)
c) Aluminum (Al)
d) Silicon (Si)
Answer: a) Sodium (Na)
Explanation: The second ionization energy is the energy required to remove a second electron after the first has been removed. For sodium, after losing one electron, it attains a stable noble gas configuration (Ne). Removing another electron from this stable configuration requires a significantly higher amount of energy compared to the other elements.
- Which of the following elements forms the most basic oxide?
a) Magnesium (Mg)
b) Aluminum (Al)
c) Silicon (Si)
d) Phosphorus (P)
Answer: a) Magnesium (Mg)
Explanation: Basicity of oxides decreases across a period from left to right as metallic character decreases. Magnesium, being an alkaline earth metal, forms a strongly basic oxide (MgO), whereas oxides of aluminum, silicon, and phosphorus are amphoteric or acidic.
- Which of the following has the smallest ionic radius?
a) Na⁺
b) Mg²⁺
c) Al³⁺
d) Si⁴⁺
Answer: d) Si⁴⁺
Explanation: Ionic radius decreases as the charge on the ion increases for a given period. As we move from Na⁺ to Si⁴⁺, the nuclear charge increases, pulling the remaining electrons closer to the nucleus, leading to a smaller ionic radius for Si⁴⁺.
- Which of the following species is the most paramagnetic?
a) F⁻
b) O²⁻
c) N³⁻
d) Na⁺
Answer: b) O²⁻
Explanation: Paramagnetism is associated with the presence of unpaired electrons. Among these species, O²⁻ has unpaired electrons in its p-orbital, making it paramagnetic, while the others have fully paired electrons and are diamagnetic.
- Which of the following properties does not increase as you move from left to right across a period?
a) Electronegativity
b) Ionization energy
c) Atomic radius
d) Electron affinity
Answer: c) Atomic radius
Explanation: As we move from left to right across a period, atomic radius decreases due to the increase in effective nuclear charge, which pulls the electrons closer to the nucleus. Electronegativity, ionization energy, and electron affinity all increase across a period due to the stronger pull on the electrons.
- Which of the following elements has the most metallic character?
a) Calcium (Ca)
b) Magnesium (Mg)
c) Potassium (K)
d) Beryllium (Be)
Answer: c) Potassium (K)
Explanation: Metallic character increases down a group and decreases across a period. Potassium is farther down Group 1, making it more metallic than the other options.
- The electron affinity of which of the following elements is lowest?
a) Nitrogen (N)
b) Oxygen (O)
c) Phosphorus (P)
d) Sulfur (S)
Answer: a) Nitrogen (N)
Explanation: Nitrogen has a half-filled p-orbital, which is relatively stable. This makes it less favorable for nitrogen to accept an additional electron, leading to a lower electron affinity compared to oxygen, phosphorus, or sulfur.
- Which of the following elements exhibits the greatest tendency to lose electrons?
a) Fluorine (F)
b) Lithium (Li)
c) Sodium (Na)
d) Potassium (K)
Answer: d) Potassium (K)
Explanation: Potassium, being the largest atom among the alkali metals in this list, has a lower ionization energy and readily loses an electron to form a K⁺ ion.
- Which of the following is not a property of transition elements?
a) Formation of colored compounds
b) Formation of complex compounds
c) High reactivity with water
d) Variable oxidation states
Answer: c) High reactivity with water
Explanation: Transition elements typically have lower reactivity with water compared to alkali metals, which react vigorously with water. The other properties (colored compounds, complex formation, and variable oxidation states) are characteristic of transition elements.
- Which of the following halides has the strongest bond?
a) HF
b) HCl
c) HBr
d) HI
Answer: a) HF
Explanation: The bond strength of halides decreases as the size of the halogen atom increases. HF has the strongest bond because fluorine is the smallest halogen, resulting in a short and strong bond with hydrogen.
- Which of the following elements has the highest electronegativity?
a) Carbon (C)
b) Sulfur (S)
c) Hydrogen (H)
d) Nitrogen (N)
Answer: d) Nitrogen (N)
Explanation: Among the given elements, nitrogen is the most electronegative because it lies farther to the right and closer to the top of the periodic table compared to carbon, sulfur, and hydrogen.
- Which of the following trends is true for halogens?
a) Reactivity decreases down the group
b) Electronegativity increases down the group
c) Melting point decreases down the group
d) Atomic radius decreases down the group
Answer: a) Reactivity decreases down the group
Explanation: The reactivity of halogens decreases as you move down the group due to increasing atomic size and decreasing ability to gain an electron.
- The correct order of atomic radius is:
a) Na > K > Rb > Cs
b) Cs > Rb > K > Na
c) Rb > K > Na > Cs
d) Na > Cs > K > Rb
Answer: b) Cs > Rb > K > Na
Explanation: Atomic radius increases down a group. Cesium, being the farthest down Group 1, has the largest atomic radius, followed by rubidium, potassium, and sodium.
- Which element is most likely to form a negative ion?
a) Sodium (Na)
b) Fluorine (F)
c) Calcium (Ca)
d) Aluminum (Al)
Answer: b) Fluorine (F)
Explanation: Fluorine is the most electronegative element and has a strong tendency to gain an electron and form a negative ion (F⁻).
- Which of the following is the most electronegative group in the periodic table?
a) Alkali metals
b) Transition metals
c) Noble gases
d) Halogens
Answer: d) Halogens
Explanation: Halogens are the most electronegative group in the periodic table because they are one electron short of achieving a stable noble gas configuration.
- Which of the following pairs of elements would exhibit the greatest difference in atomic size?
a) Sodium and Magnesium
b) Fluorine and Chlorine
c) Potassium and Rubidium
d) Carbon and Silicon
Answer: d) Carbon and Silicon
Explanation: Carbon and silicon belong to the same group but different periods. Atomic size increases significantly as you move down a group due to the addition of electron shells.
- Which element has the highest ionization energy in Period 3?
a) Sodium (Na)
b) Magnesium (Mg)
c) Sulfur (S)
d) Argon (Ar)
Answer: d) Argon (Ar)
Explanation: Argon is a noble gas with a full valence shell, making it very stable and requiring a large amount of energy to remove an electron, hence the highest ionization energy in Period 3.
- Which of the following elements has the greatest tendency to form covalent bonds?
a) Oxygen (O)
b) Neon (Ne)
c) Sodium (Na)
d) Potassium (K)
Answer: a) Oxygen (O)
Explanation: Oxygen is highly electronegative and tends to share electrons to form covalent bonds. Neon, being a noble gas, does not form bonds easily, while sodium and potassium typically form ionic bonds.
- Which of the following is an amphoteric oxide?
a) Na₂O
b) MgO
c) Al₂O₃
d) SO₃
Answer: c) Al₂O₃
Explanation: Amphoteric oxides react with both acids and bases. Al₂O₃ is amphoteric, whereas Na₂O and MgO are basic oxides, and SO₃ is an acidic oxide.
- Which of the following has the highest electron affinity?
a) Oxygen (O)
b) Fluorine (F)
c) Chlorine (Cl)
d) Bromine (Br)
Answer: c) Chlorine (Cl)
Explanation: Chlorine has the highest electron affinity, even higher than fluorine, due to lower electron-electron repulsion in chlorine’s larger atomic size.
- Which of the following elements would have the lowest melting point?
a) Sodium (Na)
b) Magnesium (Mg)
c) Potassium (K)
d) Calcium (Ca)
Answer: c) Potassium (K)
Explanation: Among the alkali and alkaline earth metals listed, potassium has the largest atomic size and the weakest metallic bonding, leading to a lower melting point.
- Which of the following is true about ionization energy?
a) It decreases across a period
b) It increases down a group
c) It increases across a period
d) It remains constant across a period
Answer: c) It increases across a period
Explanation: Ionization energy increases across a period due to increasing nuclear charge, which makes it harder to remove an electron as you move from left to right.
- Which of the following elements has the lowest ionization energy?
a) Lithium (Li)
b) Sodium (Na)
c) Potassium (K)
d) Cesium (Cs)
Answer: d) Cesium (Cs)
Explanation: Cesium, being the farthest down in Group 1, has the largest atomic size and the weakest attraction between the nucleus and the outermost electron, leading to the lowest ionization energy.
- Which group in the periodic table has the highest ionization energies?
a) Alkali metals
b) Transition metals
c) Halogens
d) Noble gases
Answer: d) Noble gases
Explanation: Noble gases have very high ionization energies because they have a full valence shell and are very stable, making it difficult to remove an electron.
- Which of the following trends is true as you move down a group in the periodic table?
a) Electronegativity increases
b) Atomic radius decreases
c) Ionization energy decreases
d) Electron affinity increases
Answer: c) Ionization energy decreases
Explanation: Ionization energy decreases as you move down a group because the outermost electrons are farther from the nucleus, and the attraction is weaker.
- Which of the following trends is observed in atomic size across a period?
a) Increases from left to right
b) Decreases from left to right
c) Remains constant
d) Increases then decreases
Answer: b) Decreases from left to right
Explanation: As you move across a period from left to right, atomic size decreases due to the increasing nuclear charge, which pulls electrons closer to the nucleus.
- Which of the following has the greatest electron affinity?
a) Sulfur (S)
b) Oxygen (O)
c) Selenium (Se)
d) Tellurium (Te)
Answer: a) Sulfur (S)
Explanation: Sulfur has a higher electron affinity than oxygen due to reduced electron-electron repulsion in its larger atomic size compared to oxygen.
- Which of the following statements is correct about d-block elements?
a) They typically form only one oxidation state
b) They form colored compounds
c) They do not form complex compounds
d) Their ionization energies decrease across the period
Answer: b) They form colored compounds
Explanation: d-block elements, or transition metals, form colored compounds due to the presence of unpaired d-electrons that absorb light and undergo electronic transitions.
- Which of the following has the smallest ionic radius?
a) K⁺
b) Ca²⁺
c) Cl⁻
d) S²⁻
Answer: b) Ca²⁺
Explanation: Ca²⁺ has a smaller ionic radius compared to K⁺, Cl⁻, and S²⁻ because it has lost two electrons, leading to a smaller, more compact ion.
- Which element is most likely to form an anion?
a) Potassium (K)
b) Magnesium (Mg)
c) Chlorine (Cl)
d) Aluminum (Al)
Answer: c) Chlorine (Cl)
Explanation: Chlorine, being a non-metal with high electronegativity, has a strong tendency to gain an electron and form a negative ion (Cl⁻).
- Which of the following has the lowest electron affinity?
a) Phosphorus (P)
b) Sulfur (S)
c) Oxygen (O)
d) Nitrogen (N)
Answer: d) Nitrogen (N)
Explanation: Nitrogen has a half-filled p-orbital, which makes it relatively stable. It resists gaining an additional electron, giving it a lower electron affinity compared to phosphorus, sulfur, and oxygen.
- Which of the following oxides is acidic?
a) Na₂O
b) MgO
c) CO₂
d) CaO
Answer: c) CO₂
Explanation: CO₂ is a non-metal oxide and reacts with water to form carbonic acid, making it an acidic oxide. The others are basic oxides.
- Which element has the lowest first ionization energy?
a) Fluorine (F)
b) Phosphorus (P)
c) Sodium (Na)
d) Chlorine (Cl)
Answer: c) Sodium (Na)
Explanation: Sodium, being in Group 1, has a low ionization energy compared to the other elements, which are non-metals and have higher ionization energies.
- Which of the following is not a characteristic of alkali metals?
a) High ionization energy
b) Low electronegativity
c) High reactivity with water
d) Forming +1 oxidation states
Answer: a) High ionization energy
Explanation: Alkali metals have low ionization energies, making it easy for them to lose one electron and form +1 oxidation states. They are highly reactive with water.
- Which of the following has the highest melting point?
a) Lithium (Li)
b) Sodium (Na)
c) Potassium (K)
d) Cesium (Cs)
Answer: a) Lithium (Li)
Explanation: Melting points of alkali metals decrease as you move down the group. Lithium, being the smallest alkali metal, has the highest melting point.
- Which of the following is the most electronegative element?
a) Oxygen (O)
b) Nitrogen (N)
c) Chlorine (Cl)
d) Fluorine (F)
Answer: d) Fluorine (F)
Explanation: Fluorine is the most electronegative element in the periodic table due to its small size and high effective nuclear charge.
- Which of the following elements is most likely to form a cation?
a) Neon (Ne)
b) Fluorine (F)
c) Sodium (Na)
d) Oxygen (O)
Answer: c) Sodium (Na)
Explanation: Sodium, being a metal, readily loses an electron to form a cation (Na⁺). Neon is inert, and fluorine and oxygen typically form anions.
- Which of the following elements forms the most stable anion?
a) Fluorine (F)
b) Oxygen (O)
c) Nitrogen (N)
d) Sulfur (S)
Answer: a) Fluorine (F)
Explanation: Fluorine, being the most electronegative element, easily gains an electron to form a stable F⁻ anion.
- Which of the following has the greatest tendency to form complex compounds?
a) Sodium (Na)
b) Potassium (K)
c) Iron (Fe)
d) Aluminum (Al)
Answer: c) Iron (Fe)
Explanation: Transition metals like iron have d-orbitals that allow them to form complex compounds by coordinating with ligands.
- Which of the following statements is incorrect?
a) Atomic size increases down a group
b) Ionization energy decreases down a group
c) Electronegativity increases down a group
d) Metallic character increases down a group
Answer: c) Electronegativity increases down a group
Explanation: Electronegativity decreases down a group as atomic size increases, making it harder for the nucleus to attract electrons.
- Which of the following halides has the strongest ionic character?
a) HF
b) HCl
c) HBr
d) HI
Answer: a) HF
Explanation: HF has the greatest ionic character due to the large difference in electronegativity between hydrogen and fluorine. This results in a stronger attraction between the two atoms.
- Which of the following elements forms an amphoteric oxide?
a) Magnesium (Mg)
b) Silicon (Si)
c) Sulfur (S)
d) Aluminum (Al)
Answer: d) Aluminum (Al)
Explanation: Aluminum forms an amphoteric oxide (Al₂O₃), which can react with both acids and bases. The others form either basic or acidic oxides.
- Which of the following elements shows the highest second ionization energy?
a) Sodium (Na)
b) Magnesium (Mg)
c) Aluminum (Al)
d) Phosphorus (P)
Answer: a) Sodium (Na)
Explanation: After sodium loses its first electron, it achieves a stable noble gas configuration (Ne), making the second ionization energy extremely high.
- Which element is most likely to form a covalent bond?
a) Potassium (K)
b) Magnesium (Mg)
c) Chlorine (Cl)
d) Sodium (Na)
Answer: c) Chlorine (Cl)
Explanation: Chlorine, a non-metal with high electronegativity, tends to form covalent bonds by sharing electrons, unlike the metals listed, which tend to form ionic bonds.
- Which of the following elements forms a basic oxide?
a) Carbon (C)
b) Phosphorus (P)
c) Sodium (Na)
d) Sulfur (S)
Answer: c) Sodium (Na)
Explanation: Sodium, an alkali metal, forms a basic oxide (Na₂O) that reacts with water to form a basic solution.
- Which of the following has the largest atomic radius?
a) Boron (B)
b) Oxygen (O)
c) Nitrogen (N)
d) Fluorine (F)
Answer: a) Boron (B)
Explanation: Atomic radius decreases across a period from left to right. Boron is the farthest left in the periodic table compared to oxygen, nitrogen, and fluorine, and thus has the largest atomic radius.
- Which of the following elements has the smallest atomic radius?
a) Lithium (Li)
b) Sodium (Na)
c) Potassium (K)
d) Cesium (Cs)
Answer: a) Lithium (Li)
Explanation: Atomic radius increases as you move down a group. Lithium, being the first element in Group 1, has the smallest atomic radius compared to the other alkali metals.
- The first ionization energy is highest for which of the following elements?
a) Helium (He)
b) Neon (Ne)
c) Argon (Ar)
d) Krypton (Kr)
Answer: a) Helium (He)
Explanation: Helium has the highest first ionization energy of all elements because its electrons are closest to the nucleus and are held tightly by the nuclear charge.
- Which of the following elements has the most negative electron affinity?
a) Fluorine (F)
b) Chlorine (Cl)
c) Bromine (Br)
d) Iodine (I)
Answer: b) Chlorine (Cl)
Explanation: Chlorine has a more negative electron affinity than fluorine due to less electron-electron repulsion in its larger size, making it easier to accept an electron.
- Which of the following oxides is the most basic?
a) MgO
b) Al₂O₃
c) SiO₂
d) P₂O₅
Answer: a) MgO
Explanation: MgO is a basic oxide that reacts with water to form a basic solution (magnesium hydroxide). Al₂O₃ is amphoteric, and SiO₂ and P₂O₅ are acidic oxides.
- Which of the following elements would have the highest electronegativity?
a) Nitrogen (N)
b) Phosphorus (P)
c) Arsenic (As)
d) Antimony (Sb)
Answer: a) Nitrogen (N)
Explanation: Electronegativity decreases down a group. Nitrogen, being at the top of Group 15, has the highest electronegativity compared to the other elements listed.
- The most metallic element among the following is:
a) Sodium (Na)
b) Magnesium (Mg)
c) Aluminum (Al)
d) Silicon (Si)
Answer: a) Sodium (Na)
Explanation: Metallic character decreases across a period from left to right. Sodium, being the farthest left among the elements listed, has the highest metallic character.
- Which of the following elements has the highest second ionization energy?
a) Sodium (Na)
b) Magnesium (Mg)
c) Potassium (K)
d) Calcium (Ca)
Answer: a) Sodium (Na)
Explanation: After sodium loses one electron, it achieves a stable noble gas configuration (Ne). The second ionization energy is extremely high because removing another electron would disturb this stable configuration.
- Which of the following halogens has the lowest electronegativity?
a) Fluorine (F)
b) Chlorine (Cl)
c) Bromine (Br)
d) Iodine (I)
Answer: d) Iodine (I)
Explanation: Electronegativity decreases down the group. Iodine, being the largest atom, has the lowest electronegativity among the halogens listed.
- Which of the following elements has the highest melting point?
a) Oxygen (O)
b) Nitrogen (N)
c) Sulfur (S)
d) Phosphorus (P)
Answer: c) Sulfur (S)
Explanation: Sulfur has a higher melting point due to its larger atomic size and molecular structure (S₈), which requires more energy to break the bonds compared to the smaller molecules of oxygen (O₂) and nitrogen (N₂).
- Which of the following is a noble gas?
a) Hydrogen (H)
b) Oxygen (O)
c) Neon (Ne)
d) Nitrogen (N)
Answer: c) Neon (Ne)
Explanation: Neon is a noble gas, which is characterized by a full outer electron shell, making it chemically inert under most conditions.
- Which of the following elements shows the greatest tendency to form cations?
a) Fluorine (F)
b) Potassium (K)
c) Oxygen (O)
d) Nitrogen (N)
Answer: b) Potassium (K)
Explanation: Potassium is an alkali metal, which readily loses an electron to form a K⁺ cation. Fluorine and oxygen tend to form anions, and nitrogen typically forms anions or covalent bonds.
- Which of the following oxides is acidic?
a) Na₂O
b) MgO
c) SO₂
d) CaO
Answer: c) SO₂
Explanation: SO₂ is a non-metal oxide, which reacts with water to form sulfurous acid, making it an acidic oxide. Na₂O, MgO, and CaO are basic oxides.
- Which of the following elements has the smallest ionic radius?
a) Cl⁻
b) F⁻
c) K⁺
d) Na⁺
Answer: d) Na⁺
Explanation: Na⁺ has a smaller ionic radius compared to K⁺, Cl⁻, and F⁻ due to its smaller size and higher effective nuclear charge, which pulls the electrons closer to the nucleus.
- Which of the following is a d-block element?
a) Sodium (Na)
b) Chlorine (Cl)
c) Iron (Fe)
d) Phosphorus (P)
Answer: c) Iron (Fe)
Explanation: Iron (Fe) is a transition metal located in the d-block of the periodic table. Sodium, chlorine, and phosphorus are s- and p-block elements.
- Which of the following elements has the most positive electron affinity?
a) Neon (Ne)
b) Nitrogen (N)
c) Phosphorus (P)
d) Sulfur (S)
Answer: a) Neon (Ne)
Explanation: Neon, a noble gas, has a positive electron affinity because it is energetically unfavorable to add an electron to its full outer shell.
- Which of the following has the highest ionization energy?
a) Lithium (Li)
b) Beryllium (Be)
c) Boron (B)
d) Carbon (C)
Answer: d) Carbon (C)
Explanation: Ionization energy increases across a period. Carbon, being the farthest right of the elements listed, has the highest ionization energy.
- Which of the following has the largest atomic radius?
a) Sodium (Na)
b) Magnesium (Mg)
c) Aluminum (Al)
d) Silicon (Si)
Answer: a) Sodium (Na)
Explanation: Atomic radius decreases across a period from left to right. Sodium, being the first element in Period 3, has the largest atomic radius among the elements listed.
- Which of the following oxides is amphoteric?
a) Na₂O
b) MgO
c) Al₂O₃
d) SO₃
Answer: c) Al₂O₃
Explanation: Al₂O₃ is an amphoteric oxide, meaning it can react with both acids and bases. Na₂O and MgO are basic oxides, while SO₃ is an acidic oxide.
- Which of the following elements is most likely to form a covalent bond?
a) Potassium (K)
b) Magnesium (Mg)
c) Chlorine (Cl)
d) Sodium (Na)
Answer: c) Chlorine (Cl)
Explanation: Chlorine, a non-metal with high electronegativity, tends to share electrons to form covalent bonds, unlike potassium and sodium, which form ionic bonds.
- Which of the following has the lowest ionization energy?
a) Fluorine (F)
b) Nitrogen (N)
c) Oxygen (O)
d) Phosphorus (P)
Answer: d) Phosphorus (P)
Explanation: Ionization energy generally decreases down a group and increases across a period. Phosphorus has the lowest ionization energy among the elements listed because it is farther down in Group 15.
- Which of the following has the highest electron affinity?
a) Phosphorus (P)
b) Sulfur (S)
c) Oxygen (O)
d) Nitrogen (N)
Answer: b) Sulfur (S)
Explanation: Sulfur has a higher electron affinity compared to nitrogen and phosphorus because it is more electronegative and is more likely to gain an electron. Oxygen’s smaller size increases electron-electron repulsion, reducing its electron affinity.
- Which of the following halogens has the lowest melting point?
a) Fluorine (F)
b) Chlorine (Cl)
c) Bromine (Br)
d) Iodine (I)
Answer: a) Fluorine (F)
Explanation: Fluorine, being the smallest halogen and a diatomic gas at room temperature, has the lowest melting point compared to chlorine, bromine, and iodine, which are found as gases, liquids, and solids, respectively, at room temperature.
- Which of the following elements has the highest metallic character?
a) Carbon (C)
b) Silicon (Si)
c) Tin (Sn)
d) Lead (Pb)
Answer: d) Lead (Pb)
Explanation: Metallic character increases down a group. Lead, being the farthest down in Group 14, has the highest metallic character among the elements listed.
- Which of the following has the highest electronegativity?
a) Boron (B)
b) Carbon (C)
c) Nitrogen (N)
d) Oxygen (O)
Answer: d) Oxygen (O)
Explanation: Electronegativity increases across a period. Oxygen, being the farthest to the right, has the highest electronegativity of the elements listed.
- Which of the following elements has the smallest atomic size?
a) Lithium (Li)
b) Sodium (Na)
c) Potassium (K)
d) Cesium (Cs)
Answer: a) Lithium (Li)
Explanation: Atomic size increases down the group in alkali metals. Lithium, at the top of Group 1, has the smallest atomic size.
- Which of the following elements has the lowest first ionization energy?
a) Hydrogen (H)
b) Sodium (Na)
c) Potassium (K)
d) Rubidium (Rb)
Answer: d) Rubidium (Rb)
Explanation: Ionization energy decreases down a group. Rubidium, being the farthest down in Group 1 among the listed elements, has the lowest first ionization energy.
- Which of the following elements has the highest first ionization energy?
a) Helium (He)
b) Neon (Ne)
c) Argon (Ar)
d) Krypton (Kr)
Answer: a) Helium (He)
Explanation: Helium has the highest first ionization energy in the periodic table due to its small size and high effective nuclear charge, which tightly holds its electrons.
- Which of the following elements forms an acidic oxide?
a) Magnesium (Mg)
b) Sodium (Na)
c) Phosphorus (P)
d) Calcium (Ca)
Answer: c) Phosphorus (P)
Explanation: Phosphorus forms acidic oxides like P₄O₁₀, which react with water to produce phosphoric acid. Magnesium, sodium, and calcium form basic oxides.
- Which of the following halogens has the highest boiling point?
a) Fluorine (F)
b) Chlorine (Cl)
c) Bromine (Br)
d) Iodine (I)
Answer: d) Iodine (I)
Explanation: Iodine, being a solid at room temperature, has the highest boiling point compared to fluorine, chlorine, and bromine, which are gases or liquids at room temperature.
- Which of the following elements has the greatest ability to form multiple oxidation states?
a) Sodium (Na)
b) Potassium (K)
c) Iron (Fe)
d) Aluminum (Al)
Answer: c) Iron (Fe)
Explanation: Iron, a transition metal, can form multiple oxidation states (e.g., +2, +3), whereas sodium, potassium, and aluminum typically form only one oxidation state.
- Which of the following elements is most likely to exhibit allotropy?
a) Carbon (C)
b) Sodium (Na)
c) Magnesium (Mg)
d) Chlorine (Cl)
Answer: a) Carbon (C)
Explanation: Carbon exhibits allotropy, meaning it exists in different structural forms like diamond, graphite, and fullerenes. The other elements listed do not exhibit this property.
- Which of the following elements has the lowest electronegativity?
a) Fluorine (F)
b) Oxygen (O)
c) Sodium (Na)
d) Sulfur (S)
Answer: c) Sodium (Na)
Explanation: Sodium, being an alkali metal, has a very low electronegativity compared to the non-metals listed, which are more electronegative.
- Which of the following has the smallest ionic radius?
a) Na⁺
b) K⁺
c) Mg²⁺
d) Cl⁻
Answer: c) Mg²⁺
Explanation: Mg²⁺ has a smaller ionic radius compared to Na⁺, K⁺, and Cl⁻ because it has lost two electrons, leading to a higher effective nuclear charge that pulls the remaining electrons closer to the nucleus.
- Which of the following oxides is amphoteric?
a) Na₂O
b) MgO
c) ZnO
d) SO₂
Answer: c) ZnO
Explanation: ZnO is amphoteric, meaning it can react with both acids and bases. Na₂O and MgO are basic oxides, while SO₂ is an acidic oxide.
- Which of the following halogens has the lowest electronegativity?
a) Fluorine (F)
b) Chlorine (Cl)
c) Bromine (Br)
d) Iodine (I)
Answer: d) Iodine (I)
Explanation: Electronegativity decreases down the group in halogens. Iodine, being the farthest down the group, has the lowest electronegativity.
- Which of the following elements has the highest electron affinity?
a) Nitrogen (N)
b) Oxygen (O)
c) Chlorine (Cl)
d) Fluorine (F)
Answer: c) Chlorine (Cl)
Explanation: Chlorine has a higher electron affinity than fluorine due to reduced electron-electron repulsion in its larger atomic size. Oxygen and nitrogen have lower electron affinities.
- Which of the following is an alkali metal?
a) Calcium (Ca)
b) Magnesium (Mg)
c) Potassium (K)
d) Iron (Fe)
Answer: c) Potassium (K)
Explanation: Potassium is an alkali metal located in Group 1 of the periodic table, characterized by its high reactivity and tendency to form +1 ions.
- Which of the following has the highest first ionization energy?
a) Boron (B)
b) Carbon (C)
c) Nitrogen (N)
d) Oxygen (O)
Answer: c) Nitrogen (N)
Explanation: Nitrogen has a half-filled p-orbital, which makes it more stable and requires more energy to remove an electron, resulting in a higher first ionization energy than boron, carbon, and oxygen.
- Which of the following elements is a p-block element?
a) Sodium (Na)
b) Iron (Fe)
c) Nitrogen (N)
d) Calcium (Ca)
Answer: c) Nitrogen (N)
Explanation: Nitrogen is a p-block element found in Group 15. Sodium, iron, and calcium belong to the s- and d-blocks, respectively
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