2.1

Isotopes

Atoms of the same element with different number of neutrons and different masses

Relative isotopic mass

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

Relative atomic mass

Weighted mean mass compared with 1/12th of the mass of an atom of carbon-12

Charge on NO3 (nitrate)

-1

Charge on SO4 (sulfate)

2-

Unit for amount of substance

Mole symbol ‘mol’

Units of molar mass

g mol^-1

Empirical formula

The simplest whole number ratio of atoms of each element present in a compound (def not required)

Molecular formula

The number and type of atoms of each element in a molecule (def not required)

Anhydrous

A substance that contains no water.

Definition of hydrated

A substance that contains water

Definition of water of crystallisation

Water molecules that are incorporated into the crystalline structure of a compound, often essential for maintaining its stability and integrity.