Redox, Group 2 + 7

Loss of electrons Gain of oxygen Loss of hydrogen

Gain of electrons Loss of oxygen Gain of hydrogen

When a species is simultaneously oxidised and reduced

Silicon because it’s giant covalent

Sodium, magnesium and aluminium because they all have metallic bonds

Argon because it’s monatomic with very weak Van der Waals forces between atoms

As you go down the group the atomic radius increases because there are more electron shells

As you go down the group the first ionisation energy decreases because shielding increases, therefore there’s weaker attraction from the nucleus to the electron in its outer shell

As you go down the group the melting point decreases because as the ions become larger, the strength of the metallic bond decreases

X + 2H2O –> X(OH)2 + H2

Mg + H2O –> MgO + H2

As you go down the group, reactivity increases because there is increased shielding and less attraction between the nucleus and outer electron

It will react slowly with cold water

A bright white light and a white precipitate forming

Bubbles and fizzes White precipitate forms

Bubbles and fizzes Forms a colourless solution

It increases

It increases

Lime water

It decreases

Strontium sulphate and barium sulphate

Antiacid for indigestion relief Laxative

To reduce acidity of soils so more crops can be grown

Absorbing X rays Aiding the investigation of problems in digestive and bowel systems