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Element 63 · Europium (Eu)

Europium Bohr model: diagram and electrons per shell

The europium Bohr model shows a europium atom (Eu) as a small nucleus with its electrons circling it in 6 shells: 2 in shell K, 8 in shell L, 18 in shell M, 25 in shell N, 8 in shell O and 2 in shell P. This page has a rotating 3D europium Bohr model, a flat diagram, a table of the electrons in each shell and the steps to draw it yourself.

Rotate the europium Bohr model in 3D

Drag to orbit, scroll to zoom.

This is a Bohr model of europium (Eu), a simplified picture of a single europium atom. Its nucleus holds 63 protons, and a neutral europium atom has 63 electrons, arranged around it in 6 shells (2 in shell K, 8 in shell L, 18 in shell M, 25 in shell N, 8 in shell O and 2 in shell P).

Eu K · 21s2 L · 82s2 2p6 M · 183s2 3p6 3d10 N · 254s2 4p6 4d10 4f7 O · 85s2 5p6 P · 26s2

Europium Bohr model diagram

Bohr model diagram of europium: a nucleus of 63 protons with 63 electrons on 6 shells, 2 in shell K, 8 in shell L, 18 in shell M, 25 in shell N, 8 in shell O and 2 in shell P, each ring labelled with its shell letter.
The europium 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, 25 in shell N, 8 in shell O and 2 in shell P).

Europium electrons per shell

A neutral europium atom has 63 electrons, one for each of its 63 protons. They fill the shells from the nucleus outwards: 2 in shell K, 8 in shell L, 18 in shell M, 25 in shell N, 8 in shell O and 2 in shell P.

Electrons in each shell of the europium Bohr model
ShellShell number (n)ElectronsMost it can hold (2n²)Subshells
K1221s2
L2882s2 2p6
M318183s2 3p6 3d10
N425324s2 4p6 4d10 4f7
O58505s2 5p6
P62726s2

How the europium Bohr model builds up, shell by shell

Watch the europium 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, 25 in shell N, 8 in shell O and 2 in shell P) as it forms.

Animation of the europium Bohr model being built: a nucleus of 63 protons appears first, then each shell grows in around it and takes its electrons, giving 63 electrons on 6 shells (2 in shell K, 8 in shell L, 18 in shell M, 25 in shell N, 8 in shell O and 2 in shell P).
The europium 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, 25 in shell N, 8 in shell O and 2 in shell P. Protons are red, neutrons yellow and electrons blue.

How to draw the europium Bohr model

  1. Find the atomic number. Europium has atomic number 63, so a neutral atom has 63 protons and 63 electrons.
  2. Draw the nucleus. Put a circle in the centre and write Eu in it. The 63 protons sit there with the neutrons.
  3. 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.
  4. Place the electrons. Fill from the inside out: 2 in shell K, 8 in shell L, 18 in shell M, 25 in shell N, 8 in shell O and 2 in shell P.
  5. Check the total. 2 + 8 + 18 + 25 + 8 + 2 = 63, the atomic number, so every electron is accounted for.

Atomic data for the europium Bohr model

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

Identity

Symbol
Eu
Atomic number
63
Atomic mass
151.9641 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 4f7
Shorthand
[Xe] 4f7 6s2
Electrons per shell
2, 8, 18, 25, 8, 2
Outer-shell electrons
2 in shell P

Ionisation energies

I₁
547.1
I₂
1085
I₃
2404
I₄
4120

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)
231
Empirical (pm)
185
Covalent (pm)
168

Electronegativity and electron affinity

Electronegativity (Pauling)
1.2
Electron affinity (kJ/mol)
11.2

Oxidation states

+2 +3

Charges the element commonly takes in compounds.

Physical properties, abundance and history of europium

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

Physical properties

Phase at room conditions
Solid
Melting point
825.85°C (1099 K)
Boiling point
1528.85°C (1802 K)
Density
5.264 g/cm³
Thermal conductivity (W/m·K)
13.9
Specific heat (J/g·K)
0.182
Molar heat capacity (J/mol·K)
27.66
Heat of vaporisation (kJ/mol)
176

Abundance

Earth's crust (mg/kg)
2
Oceans (mg/L)
0

Discovery

Discovered by
Eugène-Anatole Demarçay
Year
1901

Common compounds

  • Europium Eu
  • Europium(III) chloride hexahydrate Cl3EuH12O6
  • Europium chloride Cl3Eu
  • Nitric acid, europium(3+) salt (3:1) EuN3O9
  • Europium nitride (EuN) EuN
  • Europium fluoride (EuF3) EuF3
  • Acetic acid, europium(3+) salt (3:1) C6H9EuO6
  • Europium, tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato-kappaO3,kappaO5)- C30H30EuF21O6

Compounds listed in the PubChem database.

Main isotopes of europium

Isotopes of europium share the same 63 protons but differ in neutrons. Natural isotopes come first, then the longest-lived others.

Main isotopes of europium: mass number, abundance, half-life and decay
Mass numberNatural abundanceHalf-lifeDecay
150–36.9 yβ⁺
15147.81 %4.6 Eyα
152–13.517 yβ⁺, β⁻
15352.19 %stable–
154–8.592 yβ⁻, EC
155–4.742 yβ⁻

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

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