One or two-letter designation referring to an element.
Element symbol
A system that shows how electrons are distributed in an atom’s orbitals.
Electron configuration
A horizontal row of elements in the periodic table.
Period
The path an electron follows as it revolves round the nucleus.
Electron shell/orbit
A measurement of distance between the outer boundary of an atom’s electron cloud and its nucleus.
Atomic radius
Elements found in the same column of the periodic table.
Group or family
An atom’s outermost electron shell.
valence shell
A set of neighbouring groups on the periodic table.
block
The minimum amount of energy required to remove an electron from an atom.
ionization energy
The negative charge that occurs when an atom receives an extra electron and becomes a negative ion.
electron affinity
