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Protactinium (Pa)
Atomic number: 91 · Category: actinide · Group 3 · Period 7 · Phase: Solid
Protactinium is a chemical element with symbol Pa and atomic number 91. It is a dense, silvery-gray metal which readily reacts with oxygen, water vapor and inorganic acids. It forms various chemical compounds where protactinium is usually present in the oxidation state +5, but can also assume +4 and even +2 or +3 states.
Atomic mass: 231.035882
Density: 15.37
Melting point: 1841 K
Boiling point: 4300 K
Appearance: bright, silvery metallic luster
Source: Wikipedia
Block: f
CPK color:#00a1ff
Electronic structure
Electron configuration: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f2 6d1
Configuration (semantic): [Rn] 5f2 6d1 7s2
Shells: 2, 8, 18, 32, 20, 9, 2
Electronegativity (Pauling): 1.5
Electron affinity: 53.03
Ionization energies: 568
Periodic position
Group: 3
Period: 7
xpos: 5
ypos: 10
Spectral/Bohr images
Image
3D Model