Element 78 · Platinum (Pt)

Platinum Bohr model: diagram and electrons per shell

The platinum Bohr model shows a platinum atom (Pt) 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, 17 in shell O and 1 in shell P. This page has a rotating 3D platinum Bohr model, a flat diagram, a table of the electrons in each shell and the steps to draw it yourself.

Rotate the platinum Bohr model in 3D

Drag to orbit, scroll to zoom.

This is a Bohr model of platinum (Pt), a simplified picture of a single platinum atom. Its nucleus holds 78 protons, and a neutral platinum atom has 78 electrons, arranged around it in 6 shells (2 in shell K, 8 in shell L, 18 in shell M, 32 in shell N, 17 in shell O and 1 in shell P).

Pt K · 21s² L · 82s² 2p⁶ M · 183s² 3p⁶ 3d¹⁰ N · 324s² 4p⁶ 4d¹⁰ 4f¹⁴ O · 175s² 5p⁶ 5d⁹ P · 16s¹

Platinum Bohr model diagram

Bohr model diagram of platinum: a nucleus of 78 protons with 78 electrons on 6 shells, 2 in shell K, 8 in shell L, 18 in shell M, 32 in shell N, 17 in shell O and 1 in shell P, each ring labelled with its shell letter. — The platinum 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, 17 in shell O and 1 in shell P).

Platinum electrons per shell

A neutral platinum atom has 78 electrons, one for each of its 78 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, 17 in shell O and 1 in shell P.

Electrons in each shell of the platinum 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	17	50	5s² 5p⁶ 5d⁹
P	6	1	72	6s¹

How the platinum Bohr model builds up, shell by shell

Watch the platinum 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, 17 in shell O and 1 in shell P) as it forms.

Animation of the platinum Bohr model being built: a nucleus of 78 protons appears first, then each shell grows in around it and takes its electrons, giving 78 electrons on 6 shells (2 in shell K, 8 in shell L, 18 in shell M, 32 in shell N, 17 in shell O and 1 in shell P). — The platinum 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, 17 in shell O and 1 in shell P. Protons are red, neutrons yellow and electrons blue.

How to draw the platinum Bohr model

Find the atomic number. Platinum has atomic number 78, so a neutral atom has 78 protons and 78 electrons.
Draw the nucleus. Put a circle in the centre and write Pt in it. The 78 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, 17 in shell O and 1 in shell P.
Check the total. 2 + 8 + 18 + 32 + 17 + 1 = 78, the atomic number, so every electron is accounted for.

Atomic data for the platinum Bohr model

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

Identity

Symbol: Pt
Atomic number: 78
Atomic mass: 195.0849 u
Family: Transition Metals
Position: group 10, period 6
Block: d-block

Electron configuration

Full: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s¹ 4f¹⁴ 5d⁹
Shorthand: [Xe] 4f¹⁴ 5d⁹ 6s¹
Electrons per shell: 2, 8, 18, 32, 17, 1
Outer-shell electrons: 1 in shell P

Ionisation energies

I₁: 870
I₂: 1791

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): 177
Empirical (pm): 135
Covalent (pm): 123
Van der Waals (pm): 175

Electronegativity and electron affinity

Electronegativity (Pauling): 2.28
Electron affinity (kJ/mol): 205.041

Oxidation states

+2 +4

Charges the element commonly takes in compounds.

Physical properties, abundance and history of platinum

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

Physical properties

Phase at room conditions: Solid
Appearance: Silvery white
Melting point: 1768.25°C (2041.4 K)
Boiling point: 3824.85°C (4098 K)
Density: 21.45 g/cm³
Thermal conductivity (W/m·K): 71.6
Specific heat (J/g·K): 0.133
Molar heat capacity (J/mol·K): 25.86
Heat of fusion (kJ/mol): 21.76
Heat of vaporisation (kJ/mol): 470

Abundance

Earth's crust (mg/kg): 0.005

Discovery

Discovered by: Antonio de Ulloa
Year: 1735

Common compounds

Cisplatin Cl2H6N2Pt
Platinum Pt
Oxaliplatin C8H14N2O4Pt
Carboplatin C6H12N2O4Pt
Platinum tetrachloride Cl4Pt
Cantide + Cisplatin Cl2H4N2Pt
Ammonium tetrachloroplatinate(II) Cl4H8N2Pt
trans-Diamminedichloroplatinum Cl2H6N2Pt+2

Compounds listed in the PubChem database.

Main isotopes of platinum

Isotopes of platinum share the same 78 protons but differ in neutrons. Natural isotopes come first, then the longest-lived others.

Main isotopes of platinum: mass number, abundance, half-life and decay
Mass number	Natural abundance	Half-life	Decay
190	0.012 %	483 Gy	α, 2β⁺
192	0.782 %	stable	α
194	32.864 %	stable	–
195	33.775 %	stable	α
196	25.211 %	stable	–
198	7.356 %	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 platinum

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