- Created by: Florence A
- Created on: 03-06-19 16:19
The Group 2 Elements
- Also known as the 'alkaline earth metals'
- These are metallic elements in the s-block of the Periodic Table
- Group 2 atoms have an outer shell s2 electron configuration, and tend to lose 2 electrons when they react
- Their compounds are white solids forming colourless solutions if soluble
- The elements are light metals with low densities and have high melting points due to strong metallic bonding and a giant metallic structure. The strength of the metallic bond decreases down the group.
- Increase in reactivity down the group - decrease in attraction between outer electrons and the nucleus.
1 of 6
Group 2 Elements With Oxygen
- These are vigorous reactions releasing energy in the form of heat
- The reactions become more violent down the groupas the reactivity of the metals increases.
- The group 2 metal oxides formed have a giant ionic lattice structure and high melting point
- Group 2 metals form 2+ ions and oxygen forms 2- ions
- The metal is the reducing agent and undergoes oxidation
- Oxygen is the oxidising agent and undergoes reduction
2 of 6
Group 2 Elements With Water
- Group 2 elements will react with water to form alkaline metal hydroxides and release H2 gas
- These reactions release energy in the form of heat. The reaction between the metal and water become more vigorous down the group as the reactivity of the metals increases.
- The solid metal reacts with water to form a colourless solution and bubbles of colourless gas appear.
- Mg is the least reactive and so only reacts rapidly with steam
3 of 6
Group 2 Elements With Dilute Acids
- Group 2 metals react with dilute acids to form a salt and hydrogen.
- The reaction becomes more violent down the group as the reactivity of the metals increases.
e.g Sr (s) + 2HCl (aq) --> SrCl2 (aq) + H2 (g)
The metal (Sr) loses electrons and is oxidised
H gains electrons and is reduced
Sr is the reducing agent
HCl is the oxidising agent
4 of 6
Group 2 Oxides With Water
- Oxides react with water to produce a solution of the metal hydroxide. This is an alkaline solution (i.e contains OH-)
- The hydroxides dissolve only slightly in water, and when the solution becomes saturated, any further metal hydroxide is a solid precipitate
- Solubility of the hydroxides increases down the group. The solution becomes correspondingly more alkaline.
5 of 6
Uses of Group 2 Compounds
- Ca(OH)2 is used by farmers and gardeners as lime to neutralise acidic soils.
- Mg(OH)2 is used as 'milk of magnesia' to neutralise the stomach acid that causes indigestion. Calcium carbonate can also be used for this. Medicines like these are called antacids.
6 of 6