Group 2

• Group 2 metals lose two electrons to form 2+ ions when they react in order to gain a full outer shell.
• The atomic radius increases down the group due to additional electron shells.
• Reactivity increases down the group as increased shielding makes the electrons easier to lose.
• Ionisation energy decreases down the group due to a greater atomic radius and increased shielding.
• Melting point decreases down the group as the atomic radius of the ions increase decreasing the strength of the metallic bond.
• Group 2 metals react with water in a redox reaction to produce a metal hydroxide and hydrogen. The hydroxide forms an alkaline solution, hence why group 2 metals are known as the alkali metals.
• Group 2 metals react with steam more violently than with water as it provides extra energy. With steam, a metal oxide and hydrogen is produced.
• Magnesium reacts slowly with water but burns with a bright white flame with steam.
• The solubility of group 2 hydroxides increases down the group.
• Magnesium hydroxide is alkaline and used in medicine as an antacid and in agriculture to neutralise acidic soils.
• The solubility of group 2 sulfates decreases down the group.
• As barium sulfate is the least soluble, it is used in medicine as barium meals which are a form of medical tracer as it cannot be absorbed by the blood.
• Barium chloride is used as a test for sulfate ions as it reacts to form barium sulfate which forms a white precipitate.
• Magnesium is used in the extraction of titanium from titanium chloride via a displacement reaction, forming magnesium chloride and titanium.
• Calcium oxide reacts with sulfur dioxide to remove it from factory pollutants, forming calcium sulfite and water.
• Group 2 ions can be identified by flame tests. Ca 2+ burns brick red, Sr 2+ burns red and Ba 2+ burns pale green.