Element 15 · Phosphorus (P)

Phosphorus Bohr model: diagram and electrons per shell

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

Rotate the phosphorus Bohr model in 3D

Drag to orbit, scroll to zoom.

This is a Bohr model of phosphorus (P), a simplified picture of a single phosphorus atom. Its nucleus holds 15 protons, and a neutral phosphorus atom has 15 electrons, arranged around it in 3 shells (2 in shell K, 8 in shell L and 5 in shell M).

P K · 21s² L · 82s² 2p⁶ M · 53s² 3p³

Phosphorus Bohr model diagram

Bohr model diagram of phosphorus: a nucleus of 15 protons with 15 electrons on 3 shells, 2 in shell K, 8 in shell L and 5 in shell M, each ring labelled with its shell letter. — The phosphorus 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 and 5 in shell M).

Phosphorus electrons per shell

A neutral phosphorus atom has 15 electrons, one for each of its 15 protons. They fill the shells from the nucleus outwards: 2 in shell K, 8 in shell L and 5 in shell M.

Electrons in each shell of the phosphorus 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	5	18	3s² 3p³

How the phosphorus Bohr model builds up, shell by shell

Watch the phosphorus 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 and 5 in shell M) as it forms.

Animation of the phosphorus Bohr model being built: a nucleus of 15 protons appears first, then each shell grows in around it and takes its electrons, giving 15 electrons on 3 shells (2 in shell K, 8 in shell L and 5 in shell M). — The phosphorus 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 and 5 in shell M. Protons are red, neutrons yellow and electrons blue.

How to draw the phosphorus Bohr model

Find the atomic number. Phosphorus has atomic number 15, so a neutral atom has 15 protons and 15 electrons.
Draw the nucleus. Put a circle in the centre and write P in it. The 15 protons sit there with the neutrons.
Draw the shells. Sketch 3 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 and 5 in shell M.
Check the total. 2 + 8 + 5 = 15, the atomic number, so every electron is accounted for.

Atomic data for the phosphorus Bohr model

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

Identity

Symbol: P
Atomic number: 15
Atomic mass: 30.9738 u
Family: Reactive Nonmetals
Position: group 15, period 3
Block: p-block

Electron configuration

Full: 1s² 2s² 2p⁶ 3s² 3p³
Shorthand: [Ne] 3s² 3p³
Electrons per shell: 2, 8, 5
Outer-shell electrons: 5 in shell M

Ionisation energies

I₁: 1011.8
I₂: 1907
I₃: 2914.1
I₄: 4963.6
I₅: 6273.9
I₆: 21267
I₇: 25431
I₈: 29872

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): 98
Empirical (pm): 100
Covalent (pm): 111
Van der Waals (pm): 180

Electronegativity and electron affinity

Electronegativity (Pauling): 2.19
Electron affinity (kJ/mol): 72.037

Oxidation states

−3 +3 +5

Charges the element commonly takes in compounds.

Physical properties, abundance and history of phosphorus

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

Physical properties

Phase at room conditions: Solid
Appearance: Colourless, waxy white, yellow, scarlet, red, violet, black
Melting point: 44.15°C (317.3 K)
Density: 1.823 g/cm³
Specific heat (J/g·K): 0.769
Molar heat capacity (J/mol·K): 23.824
Heat of fusion (kJ/mol): 2.51
Heat of vaporisation (kJ/mol): 49.8

Abundance

Earth's crust (mg/kg): 1050
Oceans (mg/L): 0.06

Discovery

Discovered by: Hennig Brand
Year: 1669

Common compounds

Parathion C10H14NO5PS
Phosphoric Acid H3O4P
Dimethoate C5H12NO3PS2
Malathion C10H19O6PS2
Adenosine Monophosphate C10H14N5O7P
Trichlorfon C4H8Cl3O4P
Coumaphos C14H16ClO5PS
Fenthion C10H15O3PS2

Compounds listed in the PubChem database.

Main isotopes of phosphorus

Isotopes of phosphorus share the same 15 protons but differ in neutrons. Natural isotopes come first, then the longest-lived others.

Main isotopes of phosphorus: mass number, abundance, half-life and decay
Mass number	Natural abundance	Half-life	Decay
30	–	2.5 min	β⁺
31	100 %	stable	–
32	–	14.269 d	β⁻
33	–	25.35 d	β⁻
34	–	12.43 s	β⁻
35	–	47.3 s	β⁻

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

More about phosphorus

Phosphorus on the periodic table – properties, isotopes, uses and the full phosphorus page.
Reactive Nonmetals – all reactive nonmetal elements and their trends.
Bohr model of every element – the Bohr model of all 118 elements.