Plutonium

Plutonium is atom number 94 — every Plutonium atom has exactly 94 protons in its center, and that number is what makes it Plutonium and nothing else. Its symbol is Pu. At room temperature it is a solid.

Plutonium is a transuranic radioactive chemical element with symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exhibits six allotropes and four oxidation states.

Summary from the source dataset, derived from Wikipedia (CC BY-SA 3.0) · original article

Plutonium sits in period 7, group 3 of the f-block. Its 94 electrons fill shells of 2, 8, 18, 32, 24, 8, 2 — written as [Rn] 5f6 7s2. Its electronegativity is 1.28 on the Pauling scale, and pulling the first electron off takes 584.7 kJ/mol. The outermost shell holds 2 electrons — the ones that do all the chemistry.

Full configuration: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f6
Ionization energies (kJ/mol): 584.7
Electron affinity: -48.33 kJ/mol · Electronegativity (Pauling): 1.28
Density: 19.816 g/cm³ · melts 912.5 K · boils 3505 K

Values exactly as published — see where the data comes from.