Chemistry: Group 2

General trend for atomic radius

Increases down the group due to more shells of electrons - creates more shielding

Reactivity

Increases down the group due to more shielding - makes electrons easier to lose

Ionisation energy

Decreases down the group due to more shielding and greater atomic radius

Melting point

Decreases down the group - larger ions have weaker attractive forces as the attractive force has to act over a much greater distance.

Group 2 metal + water equation

Metal + water -> Metal hydroxide + hydrogen gas

Solubility of hydroxides

Increases down the group

Solubility of sulphates

Decreases down the group

Group 2 metal + oxygen observations

- Beryllium: white flame
- Magnesium: bright white flame
- Calcium: Red flame
- Strontium: Red flame
- Barium: Green flame

Uses of magnesium

- Extracts titanium from titanium chloride
- Titanium chloride reduced by magnesium to extract titanium

Magnesium hydroxide used in medicine - can be an antiacid to neutralise stomach acid

Uses of calcium

- Neutralises acidic soils to allow growth of plants

- Calcium carbonate and calcium oxide can remove sulfur dioxide
- CaO (s) + 2H2O (l) + SO2 (g) -> CaSO3 (s) + 2H2O (l)
- CaCO3 (s) + 2H2O (l) + SO2 (g) -> CaSO3 (s) + 2H2O (l) + CO2 (g)