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
Uses of calcium
- Neutralises acidic soils to allow growth of plants