Indium (In)
Indium is soft enough to scratch with a fingernail, and a bent bar of it makes a high-pitched 'cry' like tin.
Indium properties
- Atomic mass
- 114.82 u
- Category
- Post-transition metal
- Group
- 13
- Period
- 5
- Block
- p-block
- State at room temp.
- Solid
- Electronegativity
- 1.78
- Melting point
- 429.75 K (156.6 °C)
- Boiling point
- 2,345 K (2,071.8 °C)
- Density
- 7.31 g/cm³
- Atomic radius
- 193 pm
- Ionization energy
- 5.786 eV
- Electron affinity
- 0.3 eV
- Radioactive
- No, has stable isotopes
- Discovered
- 1863
Indium electron configuration
- Electron configuration
- [Kr] 4d10 5s2 5p1
- Full electron configuration
- 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p1
- Electron shells
- 2 · 8 · 18 · 18 · 3
The electron configuration of Indium (In) is [Kr] 4d10 5s2 5p1. Its 49 electrons are arranged in shells as 2, 8, 18, 18, 3.
Protons, neutrons and electrons in Indium
A neutral Indium atom has 49 protons and 49 electrons. Most Indium atoms have about 66 neutrons: the atomic mass rounded to 115, minus the atomic number 49.
Neutrons are approximate: atoms of the same element can have different numbers of neutrons (isotopes). Atomic number and mass
How many valence electrons does Indium have?
3
Indium has 3 valence electrons in its outermost shell, shell 5. These are the electrons involved in chemical bonding.
Indium orbital diagram
Each box is an orbital that holds up to two electrons with opposite spins (↑↓). The inner shells are the same as the noble gas in brackets. How to write electron configurations
Molar mass of Indium
114.82 g/mol
One mole of Indium atoms (6.022 × 10²³ atoms) has a mass of 114.82 grams. Use this value to convert between grams and moles.
Indium facts
- Indium is soft enough to scratch with a fingernail, and a bent bar of it makes a high-pitched 'cry' like tin.
- Ferdinand Reich was color-blind, so his assistant Theodor Richter had to confirm the indigo spectral line that revealed indium.
- Indium (In) has atomic number 49 and is a solid at room temperature. It was discovered in 1863.
Position in the periodic table
Indium is element 49, in period 5 and group 13 of the periodic table, in the p-block.
Uses of Indium
Indium is used mostly as indium tin oxide, a transparent coating that conducts electricity and makes touchscreens, flat-panel displays, and some solar cells work. Indium compounds such as indium gallium nitride and indium phosphide are semiconductors used in LEDs, lasers, and fiber-optic communications. Its softness and low melting point also make it useful in special solders and in airtight seals for vacuum and low-temperature equipment.
Who discovered Indium?
German chemists Ferdinand Reich and Theodor Richter discovered indium in 1863 at the Freiberg Mining Academy while searching for thallium in zinc ore with a spectroscope. They named it after the bright indigo-blue line they saw in its spectrum.
Where does the name come from?
Indium is named after indigo, the deep blue dye, from the Latin indicum. Ferdinand Reich and Hieronymus Richter discovered it in 1863 by spotting a bright indigo-blue line in its spectrum.
Same group
Compare Indium
FAQ
What is the electron configuration of Indium?
The electron configuration of Indium (In) is [Kr] 4d10 5s2 5p1. Its 49 electrons are arranged in shells as 2, 8, 18, 18, 3.
How many protons, neutrons and electrons does Indium have?
A neutral Indium atom has 49 protons and 49 electrons. Most Indium atoms have about 66 neutrons: the atomic mass rounded to 115, minus the atomic number 49.
How many valence electrons does Indium have?
Indium has 3 valence electrons in its outermost shell, shell 5. These are the electrons involved in chemical bonding.
What is the molar mass of Indium?
The molar mass of Indium is 114.82 g/mol. This is the same number as its atomic mass, 114.82 u.
Is Indium a metal?
Yes. Indium is a post-transition metal, so it is a metal.
Is Indium radioactive?
Ordinary Indium is not radioactive: it has at least one stable isotope. Like every element, it also has radioactive isotopes, most of them made in laboratories.
Where is Indium on the periodic table?
Indium is element 49, in period 5 and group 13 of the periodic table, in the p-block.