Magnesium (Mg)

Definition

Magnesium is a chemical element with the symbol Mg and atomic number 12. It's a shiny gray solid which bears a close physical resemblance to the other five elements in the second column (group 2, or alkaline earth metals) of the periodic table.

Related terms

Atomic Number:

The atomic number of an element is defined as the number of protons present in its nucleus. For example, magnesium has an atomic number of 12 because it has 12 protons.

Element: An element is a substance whose atoms all have the same number of protons - i.e., the same atomic number. In this case, every atom that makes up magnesium has exactly 12 protons.

Periodic Table: The Periodic Table is a tabular arrangement of chemical elements, organized based on their atomic number, electron configuration, and recurring chemical properties. Elements are listed in order of increasing atomic number; hence you'll find magnesium at position twelve.