43 Technetium


Technetium 43  has the lowest atomic number who’s isotopes are all severely radioactive.

Physical properties
Phase: Solid
Melting point: 2430 K ​(2157 °C, ​3915 °F)
Boiling point: 4538 K ​(4265 °C, ​7709 °F)
Density near r.t. : 11 g/cm3
Heat of fusion: 33.29 kJ/mol
Heat of vaporization: 585.2 kJ/mol
Molar heat capacity: 24.27 J/(mol·K)

Atomic properties
Oxidation states: 7, 6, 5, 4, 3, 2, 1, −1, −3 ​(a strongly acidic oxide)
Electronegativity: Pauling scale: 1.9
Ionization energies 1st: 702 kJ/mol
2nd: 1470 kJ/mol
3rd: 2850 kJ/mol
Atomic radius empirical: 136 pm
Covalent radius: 147±7 pm

Crystal structure: ​hexagonal close-packed
Speed of sound thin rod: 16,200 m/s (at 20 °C)
Thermal expansion: 7.1 µm/(m·K)[2] (at r.t.)
Thermal conductivity: 50.6 W/(m·K)
Electrical resistivity: 200 nΩ·m (at 20 °C)
Magnetic ordering Paramagnetic
CAS Number: 7440-26-8