NY Regents Chemistry Exam Jan 2023
Which statement describes the charge and the radius of the magnesium ion formed when a magnesium atom loses two electrons?
(1) The Mg ion is positive and has a radius larger than the Mg atom.
(2) The Mg ion is negative and has a radius larger than the Mg atom.
(3) The Mg ion is positive and has a radius smaller than the Mg atom.
(4) The Mg ion is negative and has a radius smaller than the Mg atom
Solution: An electron has a -1 charge. Losing two electrons means losing negative charge and becoming positive. Mg ion would have a 2+ charge and a smaller radius since electrons are lost. Choice 3 is correct.