Europium (Eu)
Europium is element 63, a lanthanide in the lanthanide series (period 6). A neutral atom has 63 protons, 89 neutrons and 63 electrons, 2 of them valence electrons.
Lanthanide- Atomic number
- 63
- Atomic mass
- 151.96 u
- Valence electrons
- 2*
- Protons · neutrons
- 63 · 89
- Electrons per shell
- 2, 8, 18, 25, 8, 2
- At room temperature
- solid
Bohr model of europium
The Bohr model draws europium as a nucleus of 63 protons and 89 neutrons, with its 63 electrons on 6 circular shells: 2 in shell 1, 8 in shell 2, 18 in shell 3, 25 in shell 4, 8 in shell 5, 2 in shell 6. Press Build the atom to watch the shells fill from the inside out. The outer ring (the P shell) is dashed: the electrons there are the ones that take part in chemistry.
Real electrons don't travel in neat circles. They live in fuzzy orbitals, shown below, but the Bohr picture is the quickest way to count shells and valence electrons.
Electron configuration of europium
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f⁷
Short form (noble gas notation): [Xe] 6s² 4f⁷. The [Xe] stands for the electrons of xenon, the noble gas before it.
How many valence electrons does europium have?
Europium has 2 valence electrons.
Europium is a lanthanide, so its valence electrons are less clear-cut than for main-group elements. It has 2 electrons in its outermost shell (shell 6), and electrons in its inner f and d subshell can also take part in bonding.
Protons, neutrons and electrons
| Protons | 63 | equal to the atomic number |
|---|---|---|
| Electrons | 63 | equal to the protons in a neutral atom |
| Neutrons | 89 | mass number 152 − 63 protons |
Atoms of the same element can have different numbers of neutrons (isotopes). The count above uses the rounded atomic mass, the way it's taught in class.
Europium properties
| Symbol | Eu |
|---|---|
| Category | Lanthanide |
| Group · period · block | — · 6 · f |
| Atomic mass | 151.96 u |
| State at 25 °C | solid |
| Melting point | 1,095 K (822 °C, 1,510 °F) |
| Boiling point | 1,802 K (1,530 °C, 2,780 °F) |
| Density | 5.24 g/cm³ |
| Electronegativity (Pauling) | — |
| Atomic radius | 233 pm |
| First ionization energy | 5.67 eV |
| Electron affinity | — |
| Oxidation states | +3, +2 |
| Common ion charge | +3, +2 |
| Discovered | 1901 by Eugène-Anatole Demarçay |
Where europium sits on the periodic table
Lanthanides: Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Gadolinium, Terbium.
Questions about europium
How many valence electrons does europium have?
Europium has 2 valence electrons in its outer shell; inner d or f electrons can also bond.
How many protons, neutrons and electrons does europium have?
A neutral europium atom has 63 protons and 63 electrons. Its most common form has about 89 neutrons (mass number 152 − 63 protons).
What is the electron configuration of europium?
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f⁷, written in short form as [Xe] 6s² 4f⁷.
What does the Bohr model of europium look like?
A nucleus of 63 protons and 89 neutrons, circled by 6 electron shells holding 2, 8, 18, 25, 8, 2 electrons.
What is the atomic number of europium?
63. The atomic number is the number of protons in the nucleus, and it is what makes an atom europium.