As magnesium loses electrons to form Mg^{2+}, how does its ionic radius change compared to its atomic radius?

• A. The ionic radius increases because the number of protons increases.
• B. The ionic radius increases because the nucleus attracts the remaining electrons more strongly.
• C. The ionic radius decreases because the loss of electrons reduces electron-electron repulsion.
• D. The ionic radius remains the same as the atomic radius.

Answer: (C)

Verified step by step guidance

1. Understand that when magnesium (Mg) forms Mg^{2+}, it loses two electrons from its neutral atomic state.
2. Recognize that losing electrons reduces the electron-electron repulsion in the electron cloud surrounding the nucleus.
3. Recall that the number of protons in the nucleus remains constant, so the effective nuclear charge experienced by the remaining electrons increases.
4. Because the effective nuclear charge increases and electron-electron repulsion decreases, the remaining electrons are pulled closer to the nucleus.
5. Conclude that this results in a decrease in the ionic radius compared to the atomic radius.