49 - Indium post-transition metal
Discovered by Ferdinand Reich in 1863
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.
Periodic table
| Shell | Electrons | Orbitals |
|---|---|---|
| 1 | 2 | 2 in 1s |
| 2 | 8 | 2 in 2s + 6 in 2p |
| 3 | 18 | 2 in 3s + 6 in 3p + 10 in 3d |
| 4 | 18 | 2 in 4s + 6 in 4p + 10 in 4d |
| 5 | 3 | 2 in 5s + 1 in 5p |
Electron shells
silvery lustrous gray Appearance
115 u Atomic Mass
1.55 Å Atomic Radius
2.35k K Boiling Point
13 Group
3 Common Oxidation States
1.42 Å Covalent Radius
7.31 g/cm³ Density
37 kJ/mol Electron Affinity
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p1 Electron Configuration
[Kr] 4d10 5s2 5p1 Electron Configuration (semantic)
1.78 Electronegativity
49 Electrons
5.79 eV First Ionization Energy
1, 2, 3 ICSD Oxidation States
558.3, 1820.7, 2704, 5210 kJ/mol Ionization Energies
430 K Melting Point
79 Mendeleev Number
26.7 J/(mol·K) Molar Heat
5 Number of Shells
3 Electron Valency
66 Neutrons
49 Atomic Number
34 Number of Isotopes
1, 2, 3 Oxidation States
5 Period
Solid Phase
49 Protons
2, 8, 18, 18, 3 Electron Shell Occupations
0.233 J/(g K) Specific Heat