Group 1 and 2 trends and reactionsEdexcel International A Level Chemistry: Mind map

Exam questions on Group 1 and 2 trends and reactions

1. The first ionisation energies of the Group 2 elements, in kJ mol⁻¹, are: beryllium 900, magnesium 738, calcium 590 and strontium 550. A student is using the data to study how ionisation energy changes down the group.
   Explain why the first ionisation energy decreases down Group 2.2 marks
2. A hospital pharmacy stocks milk of magnesia (a suspension of magnesium hydroxide) as an antacid, and barium sulfate suspension for X-ray examinations of the gut. Soluble barium compounds are toxic.
   Explain why barium sulfate is safe to swallow for an X-ray examination, even though soluble barium compounds are toxic.2 marks
3. A fish farm manager finds that a pond has become acidic, with a hydrogen ion concentration of 1.0 × 10⁻³ mol dm⁻³ (pH 3.0). The pond holds 500 dm³ of water. She plans to add solid calcium oxide to neutralise the acid.
   Explain, with an ionic equation, why adding calcium oxide to the pond raises its pH.3 marks