98 Cf (Californium)
Appearance – Silvery (Radioactive metal)
Mass number – 251
Atomic weight – 251.0796 g/mol
Atomic number (Z) – 98
Electrons: 98
Protons: 98
Neutrons: 153
Period – 7
Block – f
Element category – Actinide
Electrons per shell – K1, L8, M18, N32, O28, P8, Q2
Electron configuration – 1s22s22p63s23p63d104s24p64d105s25p64f145d106s26p65f107s2
Phase – Solid
Melting point – 1173 k (900 oC)
Boiling point – 1743 k (1470 oC)
Density – 15.1 g/cm3
Half Life(s): 284 x 108
Lifetime(s): 410 x 108
Decay mode – Alpha decay
Neutron cross section (Barns) – 2900
Oxidation states – 2, 3, 4
Electronegativity – Pauling scale; 1.3
Valence – 4
Ionization energies – 1st: 608 kJ/mol
Atomic radius – 295 pm
Crystal structure – Double hexagonal close-packed
Grid Parameters – a=3.38 c=11.3
Attitude c/c – 3.26
Mohs hardness: 3 – 4
CAS Number 7440-71-3
Naming – After California, where it was discovered
Discovery – Lawrence Berkeley National Laboratory (1950)
Isotopes – 248Cf 249Cf 250Cf 251Cf 252Cf 253Cf 254Cf
Uses – It is very strong neutron emitter. It is Used in Portable metal detectors, to identifying gold and silver ores, identify water and oil layers in oil wells and to detect metal fatigue and stress in aeroplanes.
Biological Role – It is toxic due to its radioactivity
Natural abundance – It is prepared, in milligram amounts only, by the neutron bombardment of plutonium-239
#Californium
