Electronic structure

Valence

Electrons in the outer energy level

First ionisation energy

The amount of energy required to remove the first electron from gaseous atom in its ground

Orbital

Region in space where the probability

Energy level

The level where electrons of similar energy energy in an atom are grouped around the nucleus

Valency

Number of electrons gained or lost by an atom to complete its outer energy level

Nuclear charge

A measure of the ability for protons in the nucleus to attract electrons in orbit around it