Atomic Number: 91

Name: Protoactinium

Atomic symbol: Pa

Atomic Weight: 231.0359

Electron configuration: 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶4d¹⁰5s²5p⁶4f¹⁴5d¹⁰5f²6s²6p⁶6d¹7s²

Melting Point: 1600^oC

Ionic radius: 1.13 angstroms (+3); 0.98 angstroms (+4); 0.89 angstroms (+5)