Group 2

• A common name given to group 2 metals is Alkaline earth metals.
• The most reactive metal of group 2 is Barium.
• Group 2 metals have high melting and boiling points and low density.
• Group 2 metals form colourless (white) compounds.
• The highest energy electrons of group 2 metals are in the S subshell.
• The drawback of using calcium carbonate in construction is that it reacts with acid, producing carbon dioxide.
• Mg(OH)2 is used as an antacid to treat indigestion and heartburn.
• Group 2 carbonates react with acid to produce a salt and carbon dioxide.
• Calcium carbonate is present in limestone and marble and is used in building construction.
• The equation for this reaction is: CaCO3(s) + 2HCl(aq) → CaCl2(aq) + H2O(l) + CO2(g).
• Reactivity increases down group 2 because electrons are lost more easily due to a larger atomic radius and more shielding.
• The reaction between group 2 metal and water is a redox reaction.
• Beryllium is the group 2 element that doesn't react with water.
• The first ionisation energy decreases as you go down group 2 because the number of filled electron shells increases, providing increased shielding, and the atomic radius increases, weakening the force between the outer electron and nucleus, requiring less energy to remove the electron.
• The equation for the reaction of barium and water is Ba (s) + 2H 2 O (l) → Ba(OH) ₂ (aq) + H ₂ (g).
• The equation for the reaction of calcium and oxygen is 2Ca (s) + O 2 (g) → 2CaO (s).
• Magnesium reacts very slowly with water.
• The reaction between group 2 elements and oxygen is a redox reaction.
• The products when group 2 elements react with water are hydroxide and hydrogen gas.
• The equation for the reaction of calcium hydroxide and hydrochloric acid is Ca(OH) ₂ (aq) +2HCl (aq) → 2H ₂ O (l) + CaCl ₂ (aq).
• The equation for the reaction between a group 2 oxide and water is MO (s) + H 2 O (l) → M(OH) 2 (aq).
• When group 2 oxides react with water, a metal hydroxide is formed.
• The trend in hydroxide solubility down group 2 is that it increases.
• Barium hydroxide, also known as Ba(OH) ₂, creates a strong alkaline solution.
• Mg(OH) ₂ is slightly soluble, while Ba(OH) ₂ creates a strong alkaline solution.
• Beryllium oxide is the group 2 metal oxide that is insoluble in water.
• The equation for the reaction of calcium and hydrochloric acid is Ca (s) + 2HCl (aq) → CaCl 2 (s) + H 2 (g).
• The products when a group 2 element reacts with dilute acid are salt and hydrogen gas.
• Calcium hydroxide, also known as Ca(OH) ₂, is used to neutralise soil.
• When a group 2 metal reacts with water, one hydrogen atom from each water molecule is reduced.
• Magnesium hydroxide, also known as Mg(OH) ₂, is not soluble in water.