Element 51 · Antimony (Sb)

Antimony Bohr model: diagram and electrons per shell

The antimony Bohr model shows a antimony atom (Sb) 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 5 in shell O. This page has a rotating 3D antimony Bohr model, a flat diagram, a table of the electrons in each shell and the steps to draw it yourself.

Rotate the antimony Bohr model in 3D

Drag to orbit, scroll to zoom.

This is a Bohr model of antimony (Sb), a simplified picture of a single antimony atom. Its nucleus holds 51 protons, and a neutral antimony atom has 51 electrons, arranged around it in 5 shells (2 in shell K, 8 in shell L, 18 in shell M, 18 in shell N and 5 in shell O).

Sb K · 21s² L · 82s² 2p⁶ M · 183s² 3p⁶ 3d¹⁰ N · 184s² 4p⁶ 4d¹⁰ O · 55s² 5p³

Antimony Bohr model diagram

Bohr model diagram of antimony: a nucleus of 51 protons with 51 electrons on 5 shells, 2 in shell K, 8 in shell L, 18 in shell M, 18 in shell N and 5 in shell O, each ring labelled with its shell letter. — The antimony 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 5 in shell O).

Antimony electrons per shell

A neutral antimony atom has 51 electrons, one for each of its 51 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 5 in shell O.

Electrons in each shell of the antimony 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	5	50	5s² 5p³

How the antimony Bohr model builds up, shell by shell

Watch the antimony 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 5 in shell O) as it forms.

Animation of the antimony Bohr model being built: a nucleus of 51 protons appears first, then each shell grows in around it and takes its electrons, giving 51 electrons on 5 shells (2 in shell K, 8 in shell L, 18 in shell M, 18 in shell N and 5 in shell O). — The antimony 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 5 in shell O. Protons are red, neutrons yellow and electrons blue.

How to draw the antimony Bohr model

Find the atomic number. Antimony has atomic number 51, so a neutral atom has 51 protons and 51 electrons.
Draw the nucleus. Put a circle in the centre and write Sb in it. The 51 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 5 in shell O.
Check the total. 2 + 8 + 18 + 18 + 5 = 51, the atomic number, so every electron is accounted for.

Atomic data for the antimony Bohr model

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

Identity

Symbol: Sb
Atomic number: 51
Atomic mass: 121.7601 u
Family: Metalloids
Position: group 15, period 5
Block: p-block

Electron configuration

Full: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p³
Shorthand: [Kr] 4d¹⁰ 5s² 5p³
Electrons per shell: 2, 8, 18, 18, 5
Outer-shell electrons: 5 in shell O

Ionisation energies

I₁: 834
I₂: 1594.9
I₃: 2440
I₄: 4260
I₅: 5400
I₆: 10400

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): 133
Empirical (pm): 145
Covalent (pm): 140
Van der Waals (pm): 206

Electronegativity and electron affinity

Electronegativity (Pauling): 2.05
Electron affinity (kJ/mol): 101.059

Oxidation states

−3 +3 +5

Charges the element commonly takes in compounds.

Physical properties, abundance and history of antimony

Bulk properties of antimony, 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: 630.63°C (903.78 K)
Boiling point: 1634.85°C (1908 K)
Density: 6.697 g/cm³
Thermal conductivity (W/m·K): 24.43
Specific heat (J/g·K): 0.207
Molar heat capacity (J/mol·K): 25.23
Heat of fusion (kJ/mol): 20.08
Heat of vaporisation (kJ/mol): 195.2

Abundance

Earth's crust (mg/kg): 0.2
Oceans (mg/L): 0

Discovery

Year: Ancient

Common compounds

Antimony trichloride Cl3Sb
Antimony Sb
Antimony triacetate C6H9O6Sb
Triphenylantimony C18H15Sb
Antimony pentachloride Cl5Sb
Trimethyloxonium hexachlorantimonate C3H9Cl6OSb
Meglumine Antimoniate C7H18NO8Sb
Stibine H3Sb

Compounds listed in the PubChem database.

Main isotopes of antimony

Isotopes of antimony share the same 51 protons but differ in neutrons. Natural isotopes come first, then the longest-lived others.

Main isotopes of antimony: mass number, abundance, half-life and decay
Mass number	Natural abundance	Half-life	Decay
121	57.21 %	stable	–
123	42.79 %	stable	–
124	–	60.2 d	β⁻
125	–	2.758 y	β⁻
126	–	12.35 d	β⁻
127	–	3.85 d	β⁻

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

More about antimony

Antimony on the periodic table – properties, isotopes, uses and the full antimony page.
Metalloids – all metalloid elements and their trends.
Bohr model of every element – the Bohr model of all 118 elements.