Rubidium (Rb) — Atomic Data, Electron Shells & Reactions

Atomic Number (Z) 37 IUPAC Symbol Rb Standard Atomic Weight 85.468 g/mol Period / Group / Block 5 / 1 / s-block Condensed Electron Config [Kr] 5s1 Full Subshell Config 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 5s1 Principal Shell Occupancy [2, 8, 18, 8, 1] Pauling Electronegativity 0.82 First Ionization Energy 403 kJ/mol Covalent Radius 220 pm Melting Point 312.45 K (39.30 °C) Boiling Point 961 K (687.85 °C) Density 1.532 g/cm³ Oxidation States +1