Topic 1.2 Periodicity

mpt/bpt increases then decreases (increases- with metallic bonding) (decreases- with covalent bonding)

The bigger the ion: 1+, 2+, 3+… the stronger the attraction towards the sea of delocalised electrons so harder to break when melting.

Atomic radius decreases along a period -More protons-> bigger nuclear attraction-> pulls electron closer-> smaller atomic radius (the bigger the atomic number, the smaller the atomic radius).

-Nuclear charge increases -Slight decrease in atomic radius -Slight but negligible increase in shielding This leads to a decrease in energy of the outermost electron and a general increase in ionisation energy across the period.

-Nuclear charge increases but: -each quantum shell is higher energy -huge increase in atomic radius which partially counteract the increase in nuclear charge -huge increase in shielding The increases in shielding and atomic radius lead to a general decrease in IE down a group.