MCQ Collection
NAT MCQs
Practice NAT questions with answers and explanations.
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Correct Answer: C. 2
Explanation:
The Pauli exclusion principle allows two electrons per orbital.
They must have opposite spin quantum numbers.
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Correct Answer: D. 1
Explanation:
An s subshell contains one orbital.
It can hold a maximum of two electrons.
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Correct Answer: A. 3
Explanation:
A p subshell contains three orbitals.
It can hold a maximum of six electrons.
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Correct Answer: B. 10
Explanation:
A d subshell contains five orbitals.
At two electrons per orbital, it holds ten electrons.
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Correct Answer: C. Electrons fill lower-energy orbitals before higher-energy ones
Explanation:
The Aufbau principle guides ground-state configurations.
Actual filling order follows orbital energies.
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Correct Answer: D. Electrons occupy equal-energy orbitals singly before pairing
Explanation:
Hund's rule minimizes electron repulsion in degenerate orbitals.
Unpaired electrons have parallel spins before pairing.
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Correct Answer: A. No two electrons in an atom have the same four quantum numbers
Explanation:
The principle limits each orbital to two opposite-spin electrons.
It is fundamental to electron configuration.
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Correct Answer: B. Its lowest-energy electron arrangement
Explanation:
The ground state is the most stable configuration.
Energy absorption can promote electrons to excited states.
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Correct Answer: C. Atoms of the same element with different numbers of neutrons
Explanation:
Isotopes have the same atomic number but different mass numbers.
Their chemical behavior is usually similar.
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Correct Answer: C. A state with one or more electrons at higher energy than the ground state
Explanation:
Excited atoms can return to lower levels by emitting energy.
Atomic spectra arise from these transitions.
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Correct Answer: D. An atom or group with a net electric charge
Explanation:
Ions form by gaining or losing electrons.
Cations are positive and anions are negative.
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Correct Answer: D. Energy required to remove an electron from a gaseous atom or ion
Explanation:
First ionization energy removes the first electron from a neutral gaseous atom.
Successive ionization energies remove additional electrons.
