An iodine atom has 53 protons and 53 electrons. It forms an iodide ion with a charge of 1−1-1−.
Which statement correctly describes the changes when the iodide ion forms?
The proton number stays 53; the electron number increases by 1.
The proton number stays 53; the electron number decreases by 1.
The proton number increases by 1; the electron number stays 53.
The proton number decreases by 1; the electron number stays 53.
119 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.