MCQ Collection
Pakistan MCQs
Practice Pakistan questions with answers and explanations.
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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: A. It increases
Explanation:
Additional electron shells are added down a group.
This outweighs the increased nuclear charge.
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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: B. It increases
Explanation:
Effective nuclear charge generally increases across a period.
Electrons are therefore harder to remove, with some exceptions.
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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: C. It decreases
Explanation:
Valence electrons are farther from the nucleus and more shielded down a group.
They are generally easier to remove.
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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: D. Na
Explanation:
Forming Na+ removes the outer 3s electron.
The cation is smaller than the neutral atom.
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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: A. Cl-
Explanation:
Adding an electron increases electron-electron repulsion.
The anion is larger than the neutral atom.
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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: D. Electrostatic attraction between oppositely charged ions
Explanation:
Ionic bonding follows electron transfer and ion formation.
The resulting cations and anions attract in a lattice.