68 2 · 8 · 18 · 30 · 8 · 2

Erbium, Er, element 68

Lanthanide· Period 6· f-block

Configuration [Xe]4f126s2

Atomic weight
167.259Da
Phase
solid
Density
9.07g/cm³
Melting point
1,802.15K 1,529 °C
Boiling point
3,141.15K 2,868 °C
Electronegativity
1.24

Soft silvery metallic element which belongs to the lanthanoids. Six natural isotopes that are stable. Twelve artificial isotopes are known. Used in nuclear technology as a neutron absorber. It is being investigated for other possible uses. Discovered by Carl G. Mosander in 1843. Description from mendeleev.

Back to the table
The outermost shell: the valence electronsThe inner shellsThe nucleus One bead for each electron, on the ring of its shell, counted from the nucleus out. The rings turn at their own pace; the model is Bohr's picture of the atom, which places electrons in shells but not on true orbits.

Atomic properties

5 of 5 fields have a value for erbium

Atomic weight The standard atomic weight. For an element with no stable isotope, the mass of its longest-lived isotope.
167.259Da
Source: mendeleev
Electron configuration
[Xe]4f126s2
Source: mendeleev
Uncertainty of the atomic weight
0.003Da
Source: mendeleev
Electron configuration in full The electron configuration with the noble-gas core written out.
1s22s22p63s23p63d104s24p64d104f125s25p66s2
Source: Worked outfrom electron configuration
Electrons in each shell Counted from the electron configuration, from the first shell outward.
2 · 8 · 18 · 30 · 8 · 2
Source: Worked outfrom electron configuration

Screening of each subshell

Clementi's screening constants: how much of the nucleus's charge the other electrons hide from an electron in each subshell. What is left is the effective nuclear charge it feels.

SubshellScreening σEffective charge Z − σ
1s1.326366.6737
2s17.798450.2016
2p4.34663.654
3s20.923147.0769
3p20.389147.6109
3d13.639754.3603
4s31.76836.232
4p32.890835.1092
4d35.728832.2712
4f40.021627.9784
5s48.28219.718
5p50.52817.472
6s59.52388.4762