Electron configuration 5f 14 6d 10 7s 2 7p 4 (predicted) Electrons per shell: 2, 8, 18, 32, 32, 18, 6 (predicted) Physical properties; Phase at STP: solid (predicted) Melting point: 637–780 K (364–507 °C, 687–944 °F) (extrapolated) Boiling point: 1035–1135 K (762–862 °C, 1403–1583 °F) (extrapolated)