Iron

This article is about iron the metal. For the tool called iron, see ironing.

Iron is a chemical element and a metal. It is the most common chemical element on Earth (by mass), and the most widely used metal. It makes up much of the Earth's core, and is the fourth most common element in the Earth's crust. Its atomic number is 26, because each atom has 26 protons.

The metal is used a lot because it is strong and cheap. Iron is the main ingredient used to make steel. Raw iron is magnetic (attracted to magnets), and its compound magnetite is permanently magnetic.

In some regions iron was used around 1200 BCE. That event is considered the transition from bronze age to iron age.