Element 35 · Bromine (Br)

Bromine Bohr model: diagram and electrons per shell

The bromine Bohr model shows a bromine atom (Br) as a small nucleus with its electrons circling it in 4 shells: 2 in shell K, 8 in shell L, 18 in shell M and 7 in shell N. This page has a rotating 3D bromine Bohr model, a flat diagram, a table of the electrons in each shell and the steps to draw it yourself.

Rotate the bromine Bohr model in 3D

Drag to orbit, scroll to zoom.

This is a Bohr model of bromine (Br), a simplified picture of a single bromine atom. Its nucleus holds 35 protons, and a neutral bromine atom has 35 electrons, arranged around it in 4 shells (2 in shell K, 8 in shell L, 18 in shell M and 7 in shell N).

Br K · 21s² L · 82s² 2p⁶ M · 183s² 3p⁶ 3d¹⁰ N · 74s² 4p⁵

Bromine Bohr model diagram

Bohr model diagram of bromine: a nucleus of 35 protons with 35 electrons on 4 shells, 2 in shell K, 8 in shell L, 18 in shell M and 7 in shell N, each ring labelled with its shell letter. — The bromine 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 and 7 in shell N).

Bromine electrons per shell

A neutral bromine atom has 35 electrons, one for each of its 35 protons. They fill the shells from the nucleus outwards: 2 in shell K, 8 in shell L, 18 in shell M and 7 in shell N.

Electrons in each shell of the bromine 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	7	32	4s² 4p⁵

How the bromine Bohr model builds up, shell by shell

Watch the bromine 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 and 7 in shell N) as it forms.

Animation of the bromine Bohr model being built: a nucleus of 35 protons appears first, then each shell grows in around it and takes its electrons, giving 35 electrons on 4 shells (2 in shell K, 8 in shell L, 18 in shell M and 7 in shell N). — The bromine 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 and 7 in shell N. Protons are red, neutrons yellow and electrons blue.

How to draw the bromine Bohr model

Find the atomic number. Bromine has atomic number 35, so a neutral atom has 35 protons and 35 electrons.
Draw the nucleus. Put a circle in the centre and write Br in it. The 35 protons sit there with the neutrons.
Draw the shells. Sketch 4 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 and 7 in shell N.
Check the total. 2 + 8 + 18 + 7 = 35, the atomic number, so every electron is accounted for.

Atomic data for the bromine Bohr model

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

Identity

Symbol: Br
Atomic number: 35
Atomic mass: 79.904 u
Family: Halogens
Position: group 17, period 4
Block: p-block

Electron configuration

Full: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁵
Shorthand: [Ar] 3d¹⁰ 4s² 4p⁵
Electrons per shell: 2, 8, 18, 7
Outer-shell electrons: 7 in shell N

Ionisation energies

I₁: 1139.9
I₂: 2103
I₃: 3470
I₄: 4560
I₅: 5760
I₆: 8550
I₇: 9940
I₈: 18600

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): 94
Empirical (pm): 115
Covalent (pm): 114
Van der Waals (pm): 185

Electronegativity and electron affinity

Electronegativity (Pauling): 2.96
Electron affinity (kJ/mol): 324.537

Oxidation states

−1 +1 +3 +5

Charges the element commonly takes in compounds.

Physical properties, abundance and history of bromine

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

Physical properties

Phase at room conditions: Liquid
Melting point: -7.35°C (265.8 K)
Boiling point: 58.85°C (332 K)
Density: 3.1028 g/cm³
Thermal conductivity (W/m·K): 0.005
Specific heat (J/g·K): 0.474
Heat of fusion (kJ/mol): 10.57
Heat of vaporisation (kJ/mol): 29.56

Abundance

Earth's crust (mg/kg): 2.4
Oceans (mg/L): 67.3

Discovery

Discovered by: Antoine Jérôme Balard
Year: 1826

Common compounds

Bronopol C3H6BrNO4
Chlorfenapyr C15H11BrClF3N2O
Brodifacoum C31H23BrO3
Hexadecyltrimethylammonium Bromide C19H42BrN
Bromoacetic Acid C2H3BrO2
Vandetanib C22H24BrFN4O2
Methscopolamine bromide C18H24BrNO4
Halothane C2HBrClF3

Compounds listed in the PubChem database.

Main isotopes of bromine

Isotopes of bromine share the same 35 protons but differ in neutrons. Natural isotopes come first, then the longest-lived others.

Main isotopes of bromine: mass number, abundance, half-life and decay
Mass number	Natural abundance	Half-life	Decay
76	–	16.2 h	β⁺
77	–	57.04 h	β⁺
79	50.65 %	stable	–
81	49.35 %	stable	–
82	–	35.282 h	β⁻
83	–	2.374 h	β⁻

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

More about bromine

Bromine on the periodic table – properties, isotopes, uses and the full bromine page.
Halogens – all halogen elements and their trends.
Bohr model of every element – the Bohr model of all 118 elements.