Magnesium (symbol Mg, atomic number 12) is a light structural metal and the central atom of chlorophyll. It is classified as a alkaline earth metal and sits in group 2, period 3 of the periodic table.
Overview
Magnesium is the chemical element with atomic number 12 and the symbol Mg. With a standard atomic weight of 24.305, it is a alkaline earth metal. In the periodic table it occupies group 2 and period 3, and under standard conditions it is normally a solid. Magnesium is a light structural metal and the central atom of chlorophyll.
Atomic structure
An atom of Magnesium has 12 protons in its nucleus and, when neutral, 12 electrons arranged in the configuration [Ne] 3s2. Its standard atomic weight of 24.305 reflects the natural mix of its stable isotopes.
Discovery and place in the table
Magnesium was discovered in 1755 by Joseph Black. It follows Sodium (Na) and precedes Aluminium (Al) in order of atomic number.
| Atomic number | 12 |
|---|---|
| Symbol | Mg |
| Atomic mass | 24.305 |
| Category | Alkaline earth metal |
| Group | 2 |
| Period | 3 |
| Electron configuration | [Ne] 3s2 |
| Phase at STP | Solid |
| Discovered | 1755 (Joseph Black) |