Erbium (Er): electron configuration, atomic mass and facts
Erbium (Er) is element 68 of the periodic table, a lanthanide in period 6 (f-block). Its electron configuration is [Xe] 4f12 6s2, with electrons arranged in shells 2, 8, 18, 30, 8, 2, and its standard atomic weight is 167.26 u.
▶ Watch Erbium’s electrons orbit in the interactive periodic tableErbium at a glance
| Symbol | Er |
|---|---|
| Atomic number | 68 |
| Atomic mass | 167.26 u |
| Category | Lanthanide |
| Group | f-block (no group number) |
| Period | 6 |
| Block | f-block |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f12 5s2 5p6 6s2 |
| Noble-gas shorthand | [Xe] 4f12 6s2 |
| Electrons per shell | 2, 8, 18, 30, 8, 2 |
| Electronegativity (Pauling) | 1.24 |
| State at 20 °C | solid |
Where is Erbium on the periodic table?
Erbium is in period 6 of the f-block, the lanthanide row printed below the main table. It has 6 electron shells, and this row is where the 4f subshell fills.
How to work out the electron configuration of Erbium
Put 68 electrons into subshells in order of rising energy, filling each before starting the next: 1s² (2), 2s² (4), 2p⁶ (10), 3s² (12), 3p⁶ (18), 4s² (20), 3d¹⁰ (30), 4p⁶ (36), 5s² (38), 4d¹⁰ (48), 5p⁶ (54), 6s² (56), 4f¹² (68). In shorthand, [Xe] stands for the 54 electrons of xenon, giving [Xe] 4f¹² 6s².
How electronegative is Erbium?
Erbium has a Pauling electronegativity of 1.24, ranking 75 of the 100 elements with a known value (fluorine is highest at 3.98). That is low: it tends to give up electrons and form positive ions.
Frequently asked questions
What is the electron configuration of Erbium?
The electron configuration of Erbium (Er) is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f12 5s2 5p6 6s2. In noble-gas shorthand it is written [Xe] 4f12 6s2.
How many electrons does Erbium have in each shell?
Erbium has 68 electrons arranged in shells as 2, 8, 18, 30, 8, 2.
What is the atomic mass of Erbium?
The standard atomic weight of Erbium is 167.26 u, so one mole of Erbium atoms has a mass of about 167.26 g.
Is Erbium a metal?
Yes. Erbium is a lanthanide.
Explore nearby elements
More lanthanides: Terbium, Dysprosium, Holmium, Thulium, Ytterbium, Lutetium. See all elements on the periodic table.