Tellurium

52
Te
Group
16
Period
5
Block
p
Protons
Electrons
Neutrons
52
52
76
General Properties
Atomic Number
52
Atomic Weight
127.6
Mass Number
128
Category
Metalloids
Color
Silver
Radioactive
No
From the Latin word tellus, earth
Crystal Structure
Simple Trigonal
History
Tellurium was discovered in Transylvania in 1782 by Franz-Joseph Müller von Reichenstein in a mineral containing tellurium and gold.

In 1789, another Hungarian scientist, Pál Kitaibel, also discovered the element independently in an ore from Deutsch-Pilsen which had been regarded as argentiferous molybdenite.

In 1798, it was named by Martin Heinrich Klaproth who earlier isolated it from the mineral calaverite.
Electrons per shell
2, 8, 18, 18, 6
Electron Configuration
[Kr] 4d10 5s2 5p4
Te
In air, tellurium burns with a greenish-blue flames, forming the dioxide
Physical Properties
Phase
Solid
Density
6.232 g/cm3
Melting Point
722.66 K | 449.51 °C | 841.12 °F
Boiling Point
1261.15 K | 988 °C | 1810.4 °F
Heat of Fusion
17.5 kJ/mol
Heat of Vaporization
48 kJ/mol
Specific Heat Capacity
0.202 J/g·K
Abundance in Earth's crust
9.9×10-8%
Abundance in Universe
9×10-7%
Metallic
Image Credits: Images-of-elements
Metallic tellurium
CAS Number
13494-80-9
PubChem CID Number
6327182
Atomic Properties
Atomic Radius
140 pm
Covalent Radius
138 pm
Electronegativity
2.1 (Pauling scale)
Ionization Potential
9.0096 eV
Atomic Volume
20.5 cm3/mol
Thermal Conductivity
0.0235 W/cm·K
Oxidation States
-2, 2, 4, 5, 6
Applications
The primary use of tellurium is in alloys, foremost in steel and copper to improve machinability.

Tellurium is used as a basic ingredient in blasting caps, and is added to cast iron for chill control.

It is used in vulcanizing rubber and in catalysts for petroleum cracking.

Tellurium is used as a coloring agent in ceramics.
Tellurium and tellurium compounds are considered to be mildly toxic
Isotopes
Stable Isotopes
120Te, 122Te, 124Te, 125Te, 126Te
Unstable Isotopes
105Te, 106Te, 107Te, 108Te, 109Te, 110Te, 111Te, 112Te, 113Te, 114Te, 115Te, 116Te, 117Te, 118Te, 119Te, 121Te, 123Te, 127Te, 128Te, 129Te, 130Te, 131Te, 132Te, 133Te, 134Te, 135Te, 136Te, 137Te, 138Te, 139Te, 140Te, 141Te, 142Te