EDEXCEL A LEVEL CHEMISTRY TEST EXAM 2024 WITH GUARANTEED ANSWERS

Ionisation energy trend in Group 2 - correct answerAs you go down the group first ionisation energy decreases because: - Although nuclear charge is increasing - The electrons have an extra quantum shell of shielding making them easier to remove - They exist in a higher energy orbital (and/ or a further distance from the nucleus) Reactivity trend in group 2 - correct answerGroup 2 elements become more reactive going down a group as the outer two electrons are easier to remove because they have lower first ionisation energies. Group 2 reactions with oxygen - correct answer2M(s) + O₂(g) - 2MO(s) This reaction occurs vigorously when heated, but even when not heated occurs very slowly Group 2 reactions with chlorine - correct answerM(s) + Cl₂(g) - MCl(s) The group 2 element is heated with chlorine gas Group 2 reactions with water - correct answerM(s) + 2H₂O(l) - M(OH)₂(aq) + H2(g) Magnesium reacts very slowly with water, calcium, strontium and barium do so with increasing vigor. Trends of solubility of group 2 hydroxides - correct answerSolubility increases down the group as calcium hydroxide is only slightly soluble, so watch out for the state symbol change between calcium and strontium. PH value of these alkaline solutions depends not only on concentration but also on the solubility of the hydroxide. Reactions of group 2 oxides - correct answerMO(s) + H₂O(l) - M(OH)₂(aq)