Element 62 · Samarium (Sm)

Samarium Bohr model: diagram and electrons per shell

The samarium Bohr model shows a samarium atom (Sm) as a small nucleus with its electrons circling it in 6 shells: 2 in shell K, 8 in shell L, 18 in shell M, 24 in shell N, 8 in shell O and 2 in shell P. This page has a rotating 3D samarium Bohr model, a flat diagram, a table of the electrons in each shell and the steps to draw it yourself.

Rotate the samarium Bohr model in 3D

Drag to orbit, scroll to zoom.

This is a Bohr model of samarium (Sm), a simplified picture of a single samarium atom. Its nucleus holds 62 protons, and a neutral samarium atom has 62 electrons, arranged around it in 6 shells (2 in shell K, 8 in shell L, 18 in shell M, 24 in shell N, 8 in shell O and 2 in shell P).

Sm K · 21s² L · 82s² 2p⁶ M · 183s² 3p⁶ 3d¹⁰ N · 244s² 4p⁶ 4d¹⁰ 4f⁶ O · 85s² 5p⁶ P · 26s²

Samarium Bohr model diagram

Bohr model diagram of samarium: a nucleus of 62 protons with 62 electrons on 6 shells, 2 in shell K, 8 in shell L, 18 in shell M, 24 in shell N, 8 in shell O and 2 in shell P, each ring labelled with its shell letter. — The samarium 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, 24 in shell N, 8 in shell O and 2 in shell P).

Samarium electrons per shell

A neutral samarium atom has 62 electrons, one for each of its 62 protons. They fill the shells from the nucleus outwards: 2 in shell K, 8 in shell L, 18 in shell M, 24 in shell N, 8 in shell O and 2 in shell P.

Electrons in each shell of the samarium 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	24	32	4s² 4p⁶ 4d¹⁰ 4f⁶
O	5	8	50	5s² 5p⁶
P	6	2	72	6s²

How the samarium Bohr model builds up, shell by shell

Watch the samarium 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, 24 in shell N, 8 in shell O and 2 in shell P) as it forms.

Animation of the samarium Bohr model being built: a nucleus of 62 protons appears first, then each shell grows in around it and takes its electrons, giving 62 electrons on 6 shells (2 in shell K, 8 in shell L, 18 in shell M, 24 in shell N, 8 in shell O and 2 in shell P). — The samarium 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, 24 in shell N, 8 in shell O and 2 in shell P. Protons are red, neutrons yellow and electrons blue.

How to draw the samarium Bohr model

Find the atomic number. Samarium has atomic number 62, so a neutral atom has 62 protons and 62 electrons.
Draw the nucleus. Put a circle in the centre and write Sm in it. The 62 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, 24 in shell N, 8 in shell O and 2 in shell P.
Check the total. 2 + 8 + 18 + 24 + 8 + 2 = 62, the atomic number, so every electron is accounted for.

Atomic data for the samarium Bohr model

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

Identity

Symbol: Sm
Atomic number: 62
Atomic mass: 150.362 u
Family: Lanthanides
Position: period 6 of the f-block
Block: f-block

Electron configuration

Full: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f⁶
Shorthand: [Xe] 4f⁶ 6s²
Electrons per shell: 2, 8, 18, 24, 8, 2
Outer-shell electrons: 2 in shell P

Ionisation energies

I₁: 544.5
I₂: 1070
I₃: 2260
I₄: 3990

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): 238
Empirical (pm): 185
Covalent (pm): 172

Electronegativity and electron affinity

Electronegativity (Pauling): 1.17
Electron affinity (kJ/mol): 15.63

Oxidation states

Charges the element commonly takes in compounds.

Physical properties, abundance and history of samarium

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

Physical properties

Phase at room conditions: Solid
Appearance: Silvery white
Melting point: 1071.85°C (1345 K)
Boiling point: 1899.85°C (2173 K)
Density: 7.52 g/cm³
Specific heat (J/g·K): 0.197
Molar heat capacity (J/mol·K): 29.54
Heat of fusion (kJ/mol): 8.9
Heat of vaporisation (kJ/mol): 165

Abundance

Earth's crust (mg/kg): 7.05
Oceans (mg/L): 0

Discovery

Discovered by: Lecoq de Boisbaudran
Year: 1879

Common compounds

Samarium Sm-153 Lexidronam C6H17N2O12P4Sm
Samarium Sm
Samarium chloride Cl3Sm
Samarium Sm-153 Lexidronam Pentasodium C6H12N2Na5O12P4Sm
Samarium chloride hexahydrate Cl3H12O6Sm
Samarium nitrate N3O9Sm
Samarium acetate C6H9O6Sm
Samarium fluoride (SmF3) F3Sm

Compounds listed in the PubChem database.

Main isotopes of samarium

Isotopes of samarium share the same 62 protons but differ in neutrons. Natural isotopes come first, then the longest-lived others.

Main isotopes of samarium: mass number, abundance, half-life and decay
Mass number	Natural abundance	Half-life	Decay
147	15 %	106.6 Gy	α
148	11.25 %	6.3 Py	α
149	13.82 %	stable	α
150	7.37 %	stable	–
152	26.74 %	stable	–
154	22.74 %	stable	2β⁻

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

More about samarium

Samarium on the periodic table – properties, isotopes, uses and the full samarium page.
Lanthanides – all lanthanide elements and their trends.
Bohr model of every element – the Bohr model of all 118 elements.