Stable isotope Tellurium (Te)

Isotope Z(p) N(n) Atomic Mass Natural Abundance Enrichment Level Chemical Form
Te-120 52 68 119.904048 0.09% 99.90% Metal
Te-120 52 68 119.904048 0.09% 99.40-99.90% Oxide
Te-122 52 70 121.903056 2.55% 99.90% Metal
Te-122 52 70 121.903056 2.55% 99.90% Oxide
Te-123 52 71 122.904271 0.89% 99.90% Metal
Te-123 52 71 122.904271 0.89% 99.90% Oxide
Te-124 52 72 123.902819 4.74% 99.90% Metal
Te-124 52 72 123.902819 4.74% 99.90% Oxide
Te-125 52 73 124.904424 7.07% 99.00-99.90% Metal
Te-125 52 73 124.904424 7.07% 99.00-99.90% Oxide
Te-126 52 74 125.903305 18.84% 96.60-99.90% Metal
Te-126 52 74 125.903305 18.84% 96.60-99.90% Oxide
Te-128 52 76 127.904462 31.74% 99.90% Metal
Te-128 52 76 127.904462 31.74% 98.80-99.90% Oxide
Te-130 52 78 129.906229 34.08% ≥99.70% Metal
Te-130 52 78 129.906229 34.08% ≥99.70% Oxide
 

Properties of Tellurium

Name Tellurium
Symbol Te
Atomic number 52
Atomic weight 127.60
Standard state Solid at 298 °K
CAS Registry ID 13494-80-9
Group in periodic table 16
Group name Chalcogen
Period in periodic table 5
Block in periodic table p-block
Color Silvery lustrous gray
Classification Semi-metallic
Melting point 452 °C
Boiling point 989.8 °C
Vaporization point 990 ºC
Thermal conductivity (1.97–3.38) W/(m·K)
Electrical resistivity 4.36 x 105 µΩ·cm at 25 °C
Electronegativity 2.1
Heat of vaporization 48 kJ·mol-1
Heat of fusion 17.5 kJ·mol-1
Density of liquid 5.70 g/cm3 at 452 °C
Density of solid 6.24 g/cm3 
Mohs hardness scale 2.3
Electron configuration [Kr]4d105s25p4
Atomic radius 1.42 Å
Ionic radii Te+4: 0.97 Å and Te+6: 0.5 6Å (coordination number 6)
Oxidation states +2, +4, +6