Iron
TRANSITION METAL
Bohr Model: Electrons arranged in energy shells around the nucleus.
Iron is a chemical element with symbol Fe (from Latin:ferrum) 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.
Quick Facts
Atomic Number 26
Period 4
Group 8
Phase Solid
Appearance lustrous metallic with a grayish tinge
About Transition Metals
Transition metals are elements with partially filled d-orbitals. They are hard, have high melting points, and often form colored compounds.
History
Discovered By 5000 BC
Named By Unknown
Physical Properties
Atomic Mass 55.8452
Density 7.874 g/L
Molar Heat 25.1 J/(mol·K)
Phase Transition (Melting & Boiling Points)
Iron melts at 1811 K and boils at 3134 K.
Atomic Properties
Electron Config [Ar] 3d6 4s2
Electronegativity 1.83
Electron Affinity 14.785 kJ/mol
Ionization Energy 762.5 kJ/mol
Orbital Filling Diagram
This diagram visualizes electron configuration according to the Aufbau principle and Hund's rule.
Boxes represent orbitals (s, p, d, f), while arrows indicate electrons with spin up or down.
Electrons fill lower energy levels first and occupy orbitals singly before pairing.
Emission Spectrum
Photograph
External Resources
Study Guide
Atomic Number
The number of protons in the nucleus, which defines the element.
Atomic Mass
The average mass of an atom, including protons and neutrons.
Electronegativity
A measure of how strongly an atom attracts electrons in a bond.
Ionization Energy
The energy required to remove an electron from an atom.
Electron Config
The arrangement of electrons in the atom's energy shells.