Key definitions - Atomic structure and the Periodic Table

Key words you need to know

Relative Atomic Mass

The average mass of the atoms of that element compared to the mass of one twelfth of a carbon-12 atom

Relative Isotopic Mass

The mass of an atom of an isotope of the element compared to one twelfth of a carbon-12 atom

Hunds Rule

Electrons will occupy P-orbitals singly before paring takes place

First ionisation energy

The energy required to remove one mole of electrons from one mole of gaseous atoms to form one mole of gaseous positive ions

Isoelectric ions

Ions that have the same number of electrons

Periodicity

Regular repeating patterns across a period