Periodic properties

Atomic size

Distance between centre of the nucleus and the valence shell.

Ionisation potential

Amount of energy required to remove the most loosely bound electron from the valence shell to make it +ve ion.

Electron affinity

Amount of energy released when an electron is added to the valence shell to make it a -ve ion.

Electronegativity

Tendency of an element to attract the shared pair of electrons in a covalent bond.

Metallic character

Elements with no. of valence electrons = 1,2, or 3.

Non-metallic character

Elements with no. of valence electrons = 5, 6, or 7.

The only periodic properties that increase down the group and decrease across period.

• Atomic size

• Metallic character

Highest ionisation energy

Helium

Highest electron affinity

Chlorine

Highest electronegativity

Fluorine