Element 76 · Osmium (Os)

Osmium Bohr model: diagram and electrons per shell

The osmium Bohr model shows a osmium atom (Os) as a small nucleus with its electrons circling it in 6 shells: 2 in shell K, 8 in shell L, 18 in shell M, 32 in shell N, 14 in shell O and 2 in shell P. This page has a rotating 3D osmium Bohr model, a flat diagram, a table of the electrons in each shell and the steps to draw it yourself.

Rotate the osmium Bohr model in 3D

Drag to orbit, scroll to zoom.

This is a Bohr model of osmium (Os), a simplified picture of a single osmium atom. Its nucleus holds 76 protons, and a neutral osmium atom has 76 electrons, arranged around it in 6 shells (2 in shell K, 8 in shell L, 18 in shell M, 32 in shell N, 14 in shell O and 2 in shell P).

Os K · 21s² L · 82s² 2p⁶ M · 183s² 3p⁶ 3d¹⁰ N · 324s² 4p⁶ 4d¹⁰ 4f¹⁴ O · 145s² 5p⁶ 5d⁶ P · 26s²

Osmium Bohr model diagram

Bohr model diagram of osmium: a nucleus of 76 protons with 76 electrons on 6 shells, 2 in shell K, 8 in shell L, 18 in shell M, 32 in shell N, 14 in shell O and 2 in shell P, each ring labelled with its shell letter. — The osmium 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, 32 in shell N, 14 in shell O and 2 in shell P).

Osmium electrons per shell

A neutral osmium atom has 76 electrons, one for each of its 76 protons. They fill the shells from the nucleus outwards: 2 in shell K, 8 in shell L, 18 in shell M, 32 in shell N, 14 in shell O and 2 in shell P.

Electrons in each shell of the osmium 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	32	32	4s² 4p⁶ 4d¹⁰ 4f¹⁴
O	5	14	50	5s² 5p⁶ 5d⁶
P	6	2	72	6s²

How the osmium Bohr model builds up, shell by shell

Watch the osmium 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, 32 in shell N, 14 in shell O and 2 in shell P) as it forms.

Animation of the osmium Bohr model being built: a nucleus of 76 protons appears first, then each shell grows in around it and takes its electrons, giving 76 electrons on 6 shells (2 in shell K, 8 in shell L, 18 in shell M, 32 in shell N, 14 in shell O and 2 in shell P). — The osmium 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, 32 in shell N, 14 in shell O and 2 in shell P. Protons are red, neutrons yellow and electrons blue.

How to draw the osmium Bohr model

Find the atomic number. Osmium has atomic number 76, so a neutral atom has 76 protons and 76 electrons.
Draw the nucleus. Put a circle in the centre and write Os in it. The 76 protons sit there with the neutrons.
Draw the shells. Sketch 6 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, 32 in shell N, 14 in shell O and 2 in shell P.
Check the total. 2 + 8 + 18 + 32 + 14 + 2 = 76, the atomic number, so every electron is accounted for.

Atomic data for the osmium Bohr model

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

Identity

Symbol: Os
Atomic number: 76
Atomic mass: 190.233 u
Family: Transition Metals
Position: group 8, period 6
Block: d-block

Electron configuration

Full: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d⁶
Shorthand: [Xe] 4f¹⁴ 5d⁶ 6s²
Electrons per shell: 2, 8, 18, 32, 14, 2
Outer-shell electrons: 2 in shell P

Ionisation energies

I₁: 840
I₂: 1600

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): 185
Empirical (pm): 130
Covalent (pm): 129

Electronegativity and electron affinity

Electronegativity (Pauling): 2.2
Electron affinity (kJ/mol): 103.99

Oxidation states

Charges the element commonly takes in compounds.

Physical properties, abundance and history of osmium

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

Physical properties

Phase at room conditions: Solid
Appearance: Silvery, blue cast
Melting point: 3032.85°C (3306 K)
Boiling point: 5011.85°C (5285 K)
Density: 22.59 g/cm³
Specific heat (J/g·K): 0.13
Molar heat capacity (J/mol·K): 24.7
Heat of fusion (kJ/mol): 31.7
Heat of vaporisation (kJ/mol): 738

Abundance

Earth's crust (mg/kg): 0.002

Discovery

Discovered by: Smithson Tennant
Year: 1803

Common compounds

Osmium Os
Osmium Tetroxide O4Os
Dipotassium hexachloroosmate Cl6K2Os
Ammonium osmium chloride Cl6H8N2Os
Osmium hexafluoride F6Os
Osmium chloride (OsCl3) Cl3Os
Potassium osmate(VI) K2O4Os
Osmocene C10H10Os

Compounds listed in the PubChem database.

Main isotopes of osmium

Isotopes of osmium share the same 76 protons but differ in neutrons. Natural isotopes come first, then the longest-lived others.

Main isotopes of osmium: mass number, abundance, half-life and decay
Mass number	Natural abundance	Half-life	Decay
186	1.59 %	2 Py	α
187	1.96 %	stable	α
188	13.24 %	stable	α
189	16.15 %	stable	α
190	26.26 %	stable	α
192	40.78 %	stable	2β⁻, α

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

More about osmium

Osmium on the periodic table – properties, isotopes, uses and the full osmium page.
Transition Metals – all transition metal elements and their trends.
Bohr model of every element – the Bohr model of all 118 elements.