Written by the Fiveable Content Team โข Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 examโขWritten by the Fiveable Content Team โข Last updated September 2025
Definition
Magnesium is a chemical element with atomic number 12 and symbol Mg. It belongs to Group 2 (alkaline earth metals) in the periodic table and has two valence electrons.