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Pu

Plutonium

Plutonium is a chemical element with the symbol Pu and atomic number 94. It has a mass number of 244, sits in period 7 of the f-block, and is classified as an actinide.

Properties

SymbolPu
Atomic number94
Mass number244
CategoryActinide
Groupf-block — no group
Period7
Electron configuration[Rn] 5f6 7s2
Outer-shell electrons2

The figure of 244 is a mass number rather than a measured atomic weight, because this element has no stable isotope.

Calculate with plutonium

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.