Question 3 • Chemistry Honors A
A magnesium ion (Mg²⁺) and a sodium ion (Na⁺) each have 10 electrons. Mg²⁺ has 12 protons, while Na⁺ has 11, so magnesium’s stronger attraction pulls the same number of electrons closer to the nucleus. Therefore, a magnesium ion is smaller than a sodium ion.
AI-written and checked against the verified answer.