PERIODIC ELEMENT
B (Boron)

 



Atomic number : 5
Atomic mass : 10.81 g.mol-1
Electronegativity according to Pauling : 2.0
Density : 2.3 g.cm-3 at 20 °C
Melting point : 2076 °C
Boiling point : 3927 °C
Vanderwaals radius : 0.098 nm
Ionic radius : 0.027 nm
Isotopes : 2
Electronic shell : [He] 2s22p1
Energy of first ionisation : 800.5 kJ.mol-1
Energy of second ionisation : 2426.5 kJ.mol-1
Energy of third ionisation : 3658.7 kJ.mol-1
Discovered by : Sir Humphry Davy and J.L Gay-Lussac in 1808
 
Atomic Structure Uses (heat resistant alloys, Medicines)