NAT Chemistry MCQs

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.

Valence electrons largely determine chemical reactivity.
Elements in a group often share similar valence configurations.

Atomic number identifies the element.
In a neutral atom it also equals the number of electrons.

Mass number applies to a specific isotope.
It is always a whole number.

Mass equals moles multiplied by molar mass.
2×58.5 = 117 g.

Particles equal moles times Avogadro's number.
0.5×6.022×10^23 = 3.011×10^23 molecules.