Indium

Element 49 on the periodic table, symbol In, group 13, period 5.

Indium is a chemical element with symbol In and atomic number 49. It is a post-transition metallic element that is rare in Earth's crust. The metal is very soft, malleable and easily fusible, with a melting point higher than sodium, but lower than lithium or tin.

Appearance: silvery lustrous gray

Properties

Atomic Number: 49
Atomic Mass: 114.8181 u
Group: 13
Period: 5
Block: p-block
Category: Post-Transition Metal
State at 25 °C: Solid
Melting Point: 429.7 K · 156.6 °C
Boiling Point: 2,345 K · 2,071.9 °C
Density: 7.31 g/cm³
Atomic Radius: 155 pm
Electronegativity: 1.78
Oxidation States: +3
Abundance in Crust: 0.25 mg/kg
Discovered: 1863
Discovered By: Ferdinand Reich

Electron Configuration

[Kr] 4d10 5s2 5p1

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p1

Ionisation Energies (kJ/mol)

1. 558.3
2. 1,820.7
3. 2,704
4. 5,210

Elements near Indium

Elements in the same group share the number of outer electrons and behave in similar ways. Elements in the same period share a shell, so they change steadily from left to right.