3.2.2 Group 2

Group 2 Elements

Elements in the 's' block that are less reactive than Group 1 elements but have similar chemical properties.

Atomic Radius

Increases down Group 2 due to additional filled electron shells below each element.

Melting Point

Higher for Group 2 elements due to metallic bonds and giant metallic structures; decreases down the group as metallic bonds weaken.

Ionisation Energies

Group 2 elements always lose 2 electrons to form a 2+ ion; ionisation energy decreases after first ionisation.

Oxidation

Loss of electrons; all Group 2 elements lose 2 electrons to achieve a full outer shell and are always oxidized in reactions.

Reactions with Water

Group 2 elements react to form hydroxide and hydrogen gas; reactivity increases down the group.

Hydroxides Solubility

Mg(OH)2 and Ca(OH)2 are sparingly soluble, Sr(OH)2 is more soluble, and Ba(OH)2 completely dissolves.

Sulfates Solubility

MgSO4 completely dissolves, CaSO4 is fairly soluble, SrSO4 is sparingly soluble, and BaSO4 is insoluble.

Barium Sulfate Uses

Absorbs X-rays, highly toxic, and insoluble, making it safe for medical use.

Group 2 Hydroxides Uses

Mg(OH)2 for indigestion, Ba(OH)2 for X-rays, and Ca(OH)2 for neutralizing acidic soils.

Testing for Sulfate Ions

Barium sulfate forms a white precipitate when sulfate ions are present; use Barium Chloride for the test.

Extraction of Titanium

Magnesium reduces Ti4+ to extract titanium from its ore, titanium chloride.