Periodicity

Chemistry- Unit 1

Covalent Radius

The size of an atom

Covalent radius trend

• decreases along a period as the increased number of protons pulls the outer electrons closer

• increases down a group as there is a greater number of electron shells

Ionisation energy

The amount of energy required to remove one mole of electrons from one mole of gaseous atom

Electronegativity

the measure of attraction an atom has for the electrons in the bond

Ionisation energy and electronegativity trend

• increases along a group as the number of protons increases

• decreases down a group as the number of electron shells increases, causing there to be a greater screening effect