65 2 · 8 · 18 · 27 · 8 · 2

Terbium, Tb, element 65

Lanthanide· Period 6· f-block

Configuration [Xe]4f96s2

Atomic weight
158.925Da
Phase
solid
Density
8.23g/cm³
Melting point
1,632.15K 1,359 °C
Boiling point
3,503.15K 3,230 °C
Electronegativity
1.2

Silvery metallic element belonging to the lanthanoids. Tb-159 is the only stable isotope, there are seventeen artificial isotopes. Discovered by G.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 terbium

Atomic weight The standard atomic weight. For an element with no stable isotope, the mass of its longest-lived isotope.
158.9254Da
Source: mendeleev
Electron configuration
[Xe]4f96s2
Source: mendeleev
Uncertainty of the atomic weight
2×10−5Da
Source: mendeleev
Electron configuration in full The electron configuration with the noble-gas core written out.
1s22s22p63s23p63d104s24p64d104f95s25p66s2
Source: Worked outfrom electron configuration
Electrons in each shell Counted from the electron configuration, from the first shell outward.
2 · 8 · 18 · 27 · 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
1s1.273963.7261
2s17.027847.9722
2p4.307660.6924
3s20.448544.5515
3p19.985345.0147
3d13.701551.2985
4s30.9834.02
4p31.601233.3988
4d34.6930.31
4f39.135225.8648
5s45.829519.1705
5p48.03916.961
6s56.69968.3004