General - Definitions (CAP 3)

The number of protons in the nucleus of an atom.

The total number of protons and neutrons in the nucleus of an atom.

Atoms of the same element (same number of protons and electrons) with different numbers of neutrons and different masses.

A region around the nucleus that can hold up to two electrons, with opposite spins

Element which has the highest energy electron in a p sub-shell (or p orbital) (Applies to any element; s-, p-, d- or f-block)

The mass, in g, per mole of a substance. (Units are gmol-1).

The mass of an atom of an isotope compared with 1/12 of the mass of an atom of Carbon-12.

The weighted mean mass of an atom of an element compared with 1/12 of the mass of an atom of Carbon-12.

A proton donor.

A proton acceptor.

A base that dissolves in water and releases OH- ions in aqueous solution.

A compound produced when a H+ ion from an acid is replaced by a metal ion or another positive ion, such as the ammonium ion.

A proton donor which completely dissociates into its ions in solution.

A proton donor which partially dissociates into its ions in solution.

The amount of substance containing as many particles as there are carbon atoms in exactly 12g of Carbon-12.

The number of particles per mole of a substance (6.02 x 1023 mol-1)

The gas volume per mole of a substance. This is 24.0 dm3mol-1 at room temperature and pressure (RTP).

The simplest whole number ratio of atoms of each element present in a compound.

The actual number and type of atoms of each element in a molecule.

The water present in a compound giving the compound a crystalline appearance.

When all the waters of crystallisation have been removed from a compound.

When water of crystallisation is present in a crystal compound.

The electrostatic attraction between positive and negative (oppositely charged) ions.

The strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms.