59 2 · 8 · 18 · 21 · 8 · 2

Praseodymium, Pr, element 59

Lanthanide· Period 6· f-block

Configuration [Xe]4f36s2

Atomic weight
140.908Da
Phase
solid
Density
6.773g/cm³
Melting point
1,204.15K 931 °C
Boiling point
3,793.15K 3,520 °C
Electronegativity
1.13

Soft silvery metallic element, belongs to the lanthanoids. Only natural isotope is Pr-141 which is not radioactive. Fourteen radioactive isotopes have been artificially produced. Used in rare-earth alloys. Discovered in 1885 by C.A. von Welsbach. 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 praseodymium

Atomic weight The standard atomic weight. For an element with no stable isotope, the mass of its longest-lived isotope.
140.9077Da
Source: mendeleev
Electron configuration
[Xe]4f36s2
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.
1s22s22p63s23p63d104s24p64d104f35s25p66s2
Source: Worked outfrom electron configuration
Electrons in each shell Counted from the electron configuration, from the first shell outward.
2 · 8 · 18 · 21 · 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
1s1.169457.8306
2s15.53843.462
2p4.230654.7694
3s19.49939.501
3p19.175639.8244
3d13.847645.1524
4s28.666830.3332
4p29.943229.0568
4d32.702826.2972
4f37.899221.1008
5s41.38717.613
5p43.716515.2835
6s51.25347.7466