Which ion does magnesium form?

Which ion does magnesium form?

• A. Mg2+
• B. Mg+
• C. Mg3+
• D. Mg0

Answer: (A)

Magnesium forms a doubly charged cation because it has two electrons in its outer shell to lose in order to reach a stable, noble-gas electron arrangement. By shedding those two valence electrons, it becomes Mg2+, which is why Mg2+ is the common ion seen in compounds. Losing just one electron (to make Mg+) would leave a less stable configuration, and removing three electrons (to make Mg3+) requires much higher energy, so that ion is not typical. The neutral atom Mg0 exists only as a metal, not as an ion in most chemical contexts.

Magnesium forms a doubly charged cation because it has two electrons in its outer shell to lose in order to reach a stable, noble-gas electron arrangement. By shedding those two valence electrons, it becomes Mg2+, which is why Mg2+ is the common ion seen in compounds. Losing just one electron (to make Mg+) would leave a less stable configuration, and removing three electrons (to make Mg3+) requires much higher energy, so that ion is not typical. The neutral atom Mg0 exists only as a metal, not as an ion in most chemical contexts.