97 Bk (Berkelium)
Appearance – Silvery (Radioactive)
Mass number – 247
Atomic weight – 247.0703 g/mol
Atomic number (Z) – 97
Electrons: 97
Protons:97
Neutron:150
Period – 7
Block – f
Element category – Actinide
Electrons per shell – K2, L8, M18, N32, O27, P9, Q2
Electron configuration – 1s22s22p63s23p63d104s24p64d105s25p64f145d106s26p65f97s2
Phase – Solid
Melting point: 1259 k (986 oC)
Boiling point: 2900 k (2627 oC)
Density – α 14.78 g/cm3, β 13.25 g/cm3
Half Life (s): 435×108
Lifetime (s): 628×108
Decay mode: α decay
Neutron cross-section (Barns): 710
Heat of fusion – 7.92 kJ/mol
Oxidation states – 2, 3, 4
Electronegativity – 1.3
Valence – 4
Ionization energies – 1st: 601 kJ/mol
Atomic radius – 170 pm
Crystal structure – Double hexagonal close-packed
Grid parameters – a=3.416, c=11.07
Attitude c/a – 3.24
Thermal conductivity – 10 W/(m•k)
Magnetic ordering – Paramagnetic
CAS Number – 7440-40-6
Naming – After Berkeley, California where it was discovered
Discovery – Lawrence Berkeley National Laboratory (1949)
Isotopes – 245Bk 246Bk 247Bk 248Bk 249Bk
Uses – Because it is so rare, berkelium has no commercial or technological use at present.
Biological role – It is toxic due to its radioactivity
Natural abundance – It is made in nuclear reactors by the neutron bombardment of plutonium-239
#Berkelium
