Element 49 · Indium (In)

Indium Bohr model: diagram and electrons per shell

The indium Bohr model shows a indium atom (In) as a small nucleus with its electrons circling it in 5 shells: 2 in shell K, 8 in shell L, 18 in shell M, 18 in shell N and 3 in shell O. This page has a rotating 3D indium Bohr model, a flat diagram, a table of the electrons in each shell and the steps to draw it yourself.

Rotate the indium Bohr model in 3D

Drag to orbit, scroll to zoom.

This is a Bohr model of indium (In), a simplified picture of a single indium atom. Its nucleus holds 49 protons, and a neutral indium atom has 49 electrons, arranged around it in 5 shells (2 in shell K, 8 in shell L, 18 in shell M, 18 in shell N and 3 in shell O).

In K · 21s² L · 82s² 2p⁶ M · 183s² 3p⁶ 3d¹⁰ N · 184s² 4p⁶ 4d¹⁰ O · 35s² 5p¹

Indium Bohr model diagram

Bohr model diagram of indium: a nucleus of 49 protons with 49 electrons on 5 shells, 2 in shell K, 8 in shell L, 18 in shell M, 18 in shell N and 3 in shell O, each ring labelled with its shell letter. — The indium Bohr model drawn flat: each ring is a shell, labelled with its letter, and every dot is an electron (2 in shell K, 8 in shell L, 18 in shell M, 18 in shell N and 3 in shell O).

Indium electrons per shell

A neutral indium atom has 49 electrons, one for each of its 49 protons. They fill the shells from the nucleus outwards: 2 in shell K, 8 in shell L, 18 in shell M, 18 in shell N and 3 in shell O.

Electrons in each shell of the indium Bohr model
Shell	Shell number (n)	Electrons	Most it can hold (2n²)	Subshells
K	1	2	2	1s²
L	2	8	8	2s² 2p⁶
M	3	18	18	3s² 3p⁶ 3d¹⁰
N	4	18	32	4s² 4p⁶ 4d¹⁰
O	5	3	50	5s² 5p¹

How the indium Bohr model builds up, shell by shell

Watch the indium Bohr model come together: the nucleus first, then each shell in turn, from the innermost outwards, with its electrons joining the ring. The legend names every shell and counts its electrons, so you can read off the arrangement (2 in shell K, 8 in shell L, 18 in shell M, 18 in shell N and 3 in shell O) as it forms.

Animation of the indium Bohr model being built: a nucleus of 49 protons appears first, then each shell grows in around it and takes its electrons, giving 49 electrons on 5 shells (2 in shell K, 8 in shell L, 18 in shell M, 18 in shell N and 3 in shell O). — The indium Bohr model built up in six seconds: the nucleus first, then each shell with its electrons, ending with 2 in shell K, 8 in shell L, 18 in shell M, 18 in shell N and 3 in shell O. Protons are red, neutrons yellow and electrons blue.

How to draw the indium Bohr model

Find the atomic number. Indium has atomic number 49, so a neutral atom has 49 protons and 49 electrons.
Draw the nucleus. Put a circle in the centre and write In in it. The 49 protons sit there with the neutrons.
Draw the shells. Sketch 5 shells as rings around the nucleus. A shell holds at most 2n² electrons: 2 in the first, 8 in the second, 18 in the third and 32 in the fourth.
Place the electrons. Fill from the inside out: 2 in shell K, 8 in shell L, 18 in shell M, 18 in shell N and 3 in shell O.
Check the total. 2 + 8 + 18 + 18 + 3 = 49, the atomic number, so every electron is accounted for.

Atomic data for the indium Bohr model

The numbers behind the indium Bohr model, grouped by topic. Radii are in picometres (pm) and energies in kilojoules per mole (kJ/mol).

Identity

Symbol: In
Atomic number: 49
Atomic mass: 114.8181 u
Family: Post-Transition Metals
Position: group 13, period 5
Block: p-block

Electron configuration

Full: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p¹
Shorthand: [Kr] 4d¹⁰ 5s² 5p¹
Electrons per shell: 2, 8, 18, 18, 3
Outer-shell electrons: 3 in shell O

Ionisation energies

I₁: 558.3
I₂: 1820.7
I₃: 2704
I₄: 5210

Energy to remove each electron in turn (kJ/mol). A sharp jump means the next electron comes from an inner shell.

Atomic radii

Calculated (pm): 156
Empirical (pm): 155
Covalent (pm): 142
Van der Waals (pm): 193

Electronegativity and electron affinity

Electronegativity (Pauling): 1.78
Electron affinity (kJ/mol): 37.043

Oxidation states

Charges the element commonly takes in compounds.

Physical properties, abundance and history of indium

Bulk properties of indium, how common it is, who discovered it and some of its compounds.

Physical properties

Phase at room conditions: Solid
Appearance: Silvery lustrous gray
Melting point: 156.6°C (429.7485 K)
Boiling point: 2071.85°C (2345 K)
Density: 7.31 g/cm³
Thermal conductivity (W/m·K): 81.8
Specific heat (J/g·K): 0.233
Molar heat capacity (J/mol·K): 26.74
Heat of fusion (kJ/mol): 3.24
Heat of vaporisation (kJ/mol): 225.1

Abundance

Earth's crust (mg/kg): 0.25
Oceans (mg/L): 0.02

Discovery

Discovered by: Ferdinand Reich
Year: 1863

Common compounds

Indium In
Indium Trichloride Cl3In
Indium phosphide InP
Indium arsenide AsIn
Indium tribromide Br3In
Indium Tin Oxide InOSn
Indium In-111 Oxyquinoline C27H18InN3O3
Indium chloride in-111 Cl3In

Compounds listed in the PubChem database.

Main isotopes of indium

Isotopes of indium share the same 49 protons but differ in neutrons. Natural isotopes come first, then the longest-lived others.

Main isotopes of indium: mass number, abundance, half-life and decay
Mass number	Natural abundance	Half-life	Decay
108	–	58 min	β⁺
109	–	4.159 h	β⁺
110	–	4.92 h	β⁺
111	–	2.805 d	EC
113	4.281 %	stable	–
115	95.719 %	441 Ty	β⁻

α = alpha decay, β⁻ = beta-minus, β⁺ = beta-plus, EC = electron capture, SF = spontaneous fission, p / n = proton / neutron emission.

More about indium

Indium on the periodic table – properties, isotopes, uses and the full indium page.
Post-Transition Metals – all post-transition metal elements and their trends.
Bohr model of every element – the Bohr model of all 118 elements.