Element 49
Indium (In)
Indium (In) is element 49 of the periodic table, a post-transition metal in period 5, group 13 (p-block) with an atomic mass of 114.82 and is a solid at standard conditions.
At a glance
- Atomic number
- 49
- Symbol
- In
- Atomic mass
- 114.82 u
- Category
- Post-transition metals
- Period
- 5
- Group
- 13
- Block
- p-block
- Phase at STP
- solid
Electron structure
- Electron configuration
- 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p1
- Shorthand configuration
- [Kr] 4d10 5s2 5p1
- Electrons per shell
- 2, 8, 18, 18, 3
- Oxidation states
- -5, -2, -1, +1, +2, +3
Physical properties
- Melting point
- 429.75 K (156.6 °C)
- Boiling point
- 2,345 K (2,071.85 °C)
- Density
- 7.31 g/cm³
- Phase
- solid
Atomic properties
- Electronegativity (Pauling)
- 1.78
- Atomic radius
- 156 pm
- Covalent radius
- 142 pm
- Van der Waals radius
- 193 pm
- First ionization energy
- 558 kJ/mol
- Electron affinity
- 29 kJ/mol
Notable isotopes
| Isotope | Mass | Abundance | Stability |
|---|---|---|---|
| In-115 | 114.90388 | 95.71% | Stable |
Common uses
- Touchscreens
- Solar cells
- Alloys
- Semiconductors
Discovery
- Year
- 1863
- Discovered by
- Ferdinand Reich, Hieronymus Theodor Richter
- Country
- Germany
Frequently asked questions
- Is indium a metal?
- Yes. Indium is a metal, classified as a post-transition metal on the periodic table.
- How many protons does indium have?
- Indium has 49 protons. Its atomic number is 49, which is also the number of electrons in a neutral atom of indium.
- What group and period is indium in?
- Indium is in group 13 and period 5 of the periodic table, in the p-block.
- What is the atomic mass of indium?
- The atomic mass of indium is 114.82 u (unified atomic mass units).
Keep exploring
Indium's row is on the printable element property sheet, and its tile is on the periodic table wall chart - the same numbers as above, laid out for A4 or A3 paper.