Atoms of element X form X2+\mathrm{X^{2+}}X2+ ions and atoms of element Y form Y2−\mathrm{Y^{2-}}Y2− ions. The X2+\mathrm{X^{2+}}X2+ ion and the Y2−\mathrm{Y^{2-}}Y2− ion have exactly the same electronic configuration.
Which pair of elements could X and Y be?
calcium and sulfur
magnesium and sulfur
calcium and oxygen
beryllium and oxygen
56 exam-style questions on Edexcel GCSE Chemistry 2.3 Ionic bonding, covering 2.3.1 Ions and the formation of ionic bonds, 2.3.2 Naming and deducing formulae of ionic compounds, and 2.3.3 Giant ionic lattices. Each one has a worked solution and a mark scheme showing where the marks go.