Iron (Fe)

Iron is a chemical element with symbol Fe and atomic number 26. It is a metal in the first transition series. It is by mass the most common element on Earth, forming much of Earth's outer and inner core.

Atomic Number

26

Atomic Mass

55.845 u

Category

transition metal

Phase

solid

Density

7.874 g/cm³

Electron Shells

2, 8, 14, 2

Atomic Structure

Protons: 26 • Electrons: 26 • Neutrons: Varies by isotope

Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶

Discovery

Unknown