The periodic table

Basic terms and trends for the period table

Atomic radius

Atomic radius

Radius of an atom

Nuclear charge

Strength of the pull of the positive nucleus

Effective nuclear charge

Strength of the pull of the positive nucleus on its own electrons.

Electron shielding

Full electron shells shield the nucleus’ positive charge from valence shell electrons. It reduces the pull of the nucleus that the valence electrons feel.

Ionisation energy

Amount of energy required to remove an electron

First ionisation energy

How much energy is required to remove a single valence electron.

Electron affinity

Energy change that occurs when electrons are added to elements.

Electronegativity

Nucleus’s pull on the electrons in a chemical bond.