Periodicity

What are groups

Vertical columns

Show similar chemical properties

Outer shell electrons determine ms group number

What are periods

Horizontal rows

Increasing number of outer electrons

Number of hells determine period

Definition of Periodicity

The occurrence of patterns in the Periodic Table

Elements with metallic bonding

Li, Be, Na, Mg, Al, K, Ca

Elements with covalent molecular bonding

H₂, N₂, O₂, F₂, Cl₂, P₄, S₈ and fullerenes (e.g. C₆₀)

Elements with covalent network bonding

B, C (diamond, graphite), Si

Elements with monatomic bonding

Noble gases

Covalent radius definition

The measure of the size of an atom

How do you find the covalent radius

Half the distance between the nuclei of two of it’s covalently bonded atoms

What happens as you go down a group

There are more energy levels so the atoms are larger

What happens as you go along a period

Atoms are smaller due to increase in nuclear charge

Why does increasing nuclear charge make atoms smaller

The electrons are more strongly attracted to the nucleus

Why do the atoms decrease in size from lithium to neon

The increase in nuclear charge