- Which transition corresponds to the emission of X-rays in a hydrogen atom?
A) n=2 to n=1
B) n=3 to n=1
C) n=4 to n=1
D) n=5 to n=1
Answer: C) n=4 to n=1.
Explanation: The transition from n=4 to n=1 releases a significant amount of energy, resulting in the emission of X-rays.
- Which principle explains why no two electrons in an atom can have the same set of quantum numbers?
A) Aufbau principle
B) Heisenberg uncertainty principle
C) Pauli exclusion principle
D) Hund’s rule
Answer: C) Pauli exclusion principle.
Explanation: The Pauli exclusion principle states that no two electrons in an atom can occupy the same quantum state simultaneously.
- What phenomenon is responsible for the absorption of light in the context of electron transitions?
A) Emission
B) Excitation
C) Ionization
D) Reflection
Answer: B) Excitation.
Explanation: When an atom absorbs light, it excites electrons to higher energy levels, a process characterized by the absorption of photons.
- How many electrons can occupy the p subshell?
A) 2
B) 6
C) 10
D) 14
Answer: B) 6.
Explanation: The p subshell can hold a maximum of 6 electrons, as it has three orbitals (each capable of holding 2 electrons).
- Which of the following is true about the relationship between energy and frequency of electromagnetic radiation?
A) They are directly proportional.
B) They are inversely proportional.
C) They are unrelated.
D) They are constant.
Answer: A) They are directly proportional.
Explanation: Energy (E) and frequency (f) are directly proportional, expressed by the equation
E=hf.
- In a hydrogen atom, what does a transition from n=2 to n=1 produce?
A) Infrared light
B) Ultraviolet light
C) Visible light
D) X-rays
Answer: B) Ultraviolet light.
Explanation: The transition from n=2 to n=1 in hydrogen emits ultraviolet light and is part of the Lyman series.
- What type of quantum number is associated with the orientation of an electron’s spin?
A) Principal quantum number (n)
B) Azimuthal quantum number (l)
C) Magnetic quantum number (m)
D) Spin quantum number (s)
Answer: D) Spin quantum number (s).
Explanation: The spin quantum number indicates the intrinsic angular momentum or “spin” of an electron, which can be either +1/2 or -1/2.
- Which of the following series emits radiation in the infrared region?
A) Lyman series
B) Balmer series
C) Paschen series
D) Brackett series
Answer: C) Paschen series.
Explanation: The Paschen series corresponds to transitions that end at the n=3 level and emit infrared radiation.
- What is the maximum number of orbitals in the d subshell?
A) 2
B) 3
C) 5
D) 7
Answer: C) 5.
Explanation: The d subshell contains 5 orbitals, allowing it to hold a maximum of 10 electrons.
- What occurs during electron transition in a multi-electron atom compared to hydrogen?
A) Only one energy level is involved.
B) Electron-electron repulsion complicates transitions.
C) Energy levels are more quantized.
D) Only valence electrons participate.
Answer: B) Electron-electron repulsion complicates transitions.
Explanation: In multi-electron atoms, electron-electron repulsion adds complexity to energy level calculations and transitions, unlike in hydrogen.
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