group two

Group 2 + water

Metal hydroxide + hydrogen

reactivity down the group

increases (reactivity)

Group 2 + oxygen

Metal oxide - often a white solid

Group 2 oxides and hydroxides are bases so they ...

Form alkaline solutions in waterNeutralise acids

Group 2 oxide + water

Dissolves into metal ion + hydroxide ion, which is a strongly alkaline solution

How do the alkaline solutions change as you go down group 2?

They become stronger, as the hydroxides become more soluble

Group 2 hydroxides solubility

increases down the group

Group 2 carbonates solubility

decreases down the group

Thermal decomposition of group 2 carbonates produces:

:group 2 oxide + carbon dioxide

Thermal stability of carbonates increases down the group because:

Small cations at the top of group 2 as smaller atoms

So, higher charge density

Distorts the carbonate ion more

Further down the group means larger cation means less distortion so more stable

when group 2 metal + water reacts you see

fizzing and the the solid disappearing as the reaction progresses

the pH of metal hydroxides down the group

increases (pH)

why does reactivity increase

decrease in ionisation energy

bonding in group 2

giant metallic lattice

metal sulfate’s solubility down the group

decrease

Ca(OH)2 is used in

agriculture to neutralise acidic soils

Mg(OH)2 is used in

suspension to neutralise excess acid in the stomach and treat constipa