94
Pu
Plutonium
244
Plutonium
ACTINIDE
Bohr Model: Electrons arranged in energy shells around the nucleus.
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.
Quick Facts
Atomic Number 94
Period 7
Group 8
Phase Solid
Appearance silvery white, tarnishing to dark gray in air
About Actinides
Actinides are the 15 metallic elements with atomic numbers 89–103. All actinides are radioactive.
History
Discovered By Glenn T. Seaborg
Named By Unknown
Physical Properties
Atomic Mass 244
Density 19.816 g/L
Molar Heat 35.5 J/(mol·K)
Phase Transition (Melting & Boiling Points)
Plutonium melts at 912.5 K and boils at 3505 K.
Atomic Properties
Electron Config [Rn] 5f6 7s2
Electronegativity 1.28
Electron Affinity -48.33 kJ/mol
Ionization Energy 584.7 kJ/mol
Orbital Filling Diagram
This diagram visualizes electron configuration according to the Aufbau principle and Hund's rule.
Boxes represent orbitals (s, p, d, f), while arrows indicate electrons with spin up or down.
Electrons fill lower energy levels first and occupy orbitals singly before pairing.
Photograph
External Resources
Study Guide
Atomic Number
The number of protons in the nucleus, which defines the element.
Atomic Mass
The average mass of an atom, including protons and neutrons.
Electronegativity
A measure of how strongly an atom attracts electrons in a bond.
Ionization Energy
The energy required to remove an electron from an atom.
Electron Config
The arrangement of electrons in the atom's energy shells.