90 2 · 8 · 18 · 32 · 18 · 10 · 2

Thorium, Th, element 90

Actinide· Period 7· f-block

Configuration [Rn]6d27s2

Atomic weight
232.038Da
Phase
solid
Density
11.7g/cm³
Melting point
2,023.15K 1,750 °C
Boiling point
5,058.15K 4,785 °C
Electronegativity
1.3

Grey radioactive metallic element. Belongs to actinoids. Found in monazite sand in Brazil, India and the US. Thorium-232 has a half-life of 1.39x10^10 years. Can be used as a nuclear fuel for breeder reactors. Thorium-232 captures slow Neutrons and breeds uranium-233. Discovered by Jons J. Berzelius in 1829. 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 thorium

Atomic weight The standard atomic weight. For an element with no stable isotope, the mass of its longest-lived isotope.
232.0377Da
Source: mendeleev
Electron configuration
[Rn]6d27s2
Source: mendeleev
Uncertainty of the atomic weight
4×10−4Da
Source: mendeleev
Electron configuration in full The electron configuration with the noble-gas core written out.
1s22s22p63s23p63d104s24p64d104f145s25p65d106s26p66d27s2
Source: Worked outfrom electron configuration
Electrons in each shell Counted from the electron configuration, from the first shell outward.
2 · 8 · 18 · 32 · 18 · 10 · 2
Source: Worked outfrom electron configuration