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Bh

Bohrium

Bohrium is a chemical element with the symbol Bh and atomic number 107. It has a mass number of 270, sits in period 7 and group 7, and is classified as a transition metal.

Properties

SymbolBh
Atomic number107
Mass number270
CategoryTransition metal
Group7
Period7
Electron configuration[Rn] 5f14 6d5 7s2
Outer-shell electrons2

The figure of 270 is a mass number rather than a measured atomic weight, because this element has no stable isotope.

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Group 7

Atomic weights are the IUPAC 2021 standard values, abridged to the conventional five significant figures. Group, period, category and electron configuration are derived from the atomic number rather than stored, so they cannot drift out of step with it.