3.1.1 Atomic Structure

Proton number (Z)

Another name for atomic number

Mass number (M)

The number of nucleons - the number of protons + number of neutrons

Relative atomic mass (A)

The weighted mean mass of an atom in comparison to 1/12 mass C atom

Electron orbital

An area of 3 dimensional space around an atom that can hold a maximum of 2 electrons

Electron configuration and an example

The distribution of electrons of an atom in orbitals, eg. Ca: 1s²2s²2p^63s²3p^64s²

First ionisation energy

The energy required to remove one mole of electrons from one mole of gaseous atoms to form one mole of 1+ gaseous ions

Electron shielding

The innermost shell of electrons shield the nucleus attraction between outer electrons