Group 2 Metals

• Group 2 metals, also known as alkaline earth metals, lose two electrons to form 2+ ions to achieve a full outer shell.

Atomic Radius

• Atomic radius increases down the group 2 metals due to the addition of electron shells.

Reactivity

• Reactivity increases down group 2 due to greater electron shielding, making it easier to lose outer electrons.

Ionisation Energy

• First ionisation energy decreases down group 2 because of larger atomic radius and increased shielding.

Melting Point

• Melting points decrease down group 2 because larger ions in the metallic structure weaken attractive forces due to the greater distance.

Reactions with Water

• Group 2 metals react with water in a redox reaction, producing a metal hydroxide (an alkaline solution) and hydrogen.

• Magnesium reacts slowly with liquid water.

• Magnesium reacts faster with steam, burning with a bright white flame to form hydrogen and magnesium oxide (a white powder).

Solubility of Hydroxides

• Hydroxide solubility increases down group 2.
• Magnesium hydroxide is the least soluble.
• Barium hydroxide is the most soluble.
• Magnesium hydroxide is used as an antacid in medicine due to its ability to neutralise acids.
• Magnesium hydroxide is used in agriculture to neutralise acidic soils.

Solubility of Sulfates

• Sulfate solubility decreases down group 2.
• Magnesium sulfate is the most soluble.
• Barium sulfate is the least soluble.
• Barium sulfate's insolubility makes it useful in medicine as barium meals to outline the gut.
• Barium chloride tests for sulfate ions, forming barium sulfate as a white precipitate when sulfate ions are present.

Metal Extraction

• Magnesium extracts titanium from titanium chloride via a displacement reaction.

Flue Gas Removal

• Calcium oxide reacts with sulfur dioxide to remove it from factory pollutants.

• The reaction of calcium oxide and sulfur dioxide forms calcium sulfite and water.