Magnesium has an atomic number of 12. What is the most stable charge for a magnesium ion?

• A. +2
• B. +1
• C. -1
• D. 0

Answer: (A)

Verified step by step guidance

1. Identify the atomic number of magnesium, which is 12. This means magnesium has 12 protons and, in its neutral state, 12 electrons.
2. Recall that atoms tend to achieve a stable electron configuration, often resembling the nearest noble gas configuration. For magnesium, the nearest noble gas is neon, which has 10 electrons.
3. Determine how many electrons magnesium needs to lose or gain to reach the stable configuration of neon. Since magnesium has 12 electrons and neon has 10, magnesium will lose 2 electrons.
4. Losing 2 electrons results in a positive charge because the number of protons (12) exceeds the number of electrons (10) by 2, giving a charge of +2.
5. Conclude that the most stable charge for a magnesium ion is +2, as it achieves a full outer shell similar to neon.