Pakistan MCQs

Hund's rule minimizes electron repulsion in degenerate orbitals.
Unpaired electrons have parallel spins before pairing.

The principle limits each orbital to two opposite-spin electrons.
It is fundamental to electron configuration.

The ground state is the most stable configuration.
Energy absorption can promote electrons to excited states.

Isotopes have the same atomic number but different mass numbers.
Their chemical behavior is usually similar.

Excited atoms can return to lower levels by emitting energy.
Atomic spectra arise from these transitions.

Ions form by gaining or losing electrons.
Cations are positive and anions are negative.

First ionization energy removes the first electron from a neutral gaseous atom.
Successive ionization energies remove additional electrons.

A cation forms when electrons are lost.
It has more protons than electrons.

Electron affinity reflects attraction for an added electron.
Its sign and magnitude vary across the periodic table.

An anion forms when electrons are gained.
It has more electrons than protons.

Electronegativity helps predict bond polarity.
Fluorine has the highest common electronegativity.

Rutherford concluded that atoms contain a small dense positive nucleus.
Most atomic volume is empty space.