52
Te
Tellurium
127.6
Tellurium (Te)
MetalloidGroup 16Period 5p-block-block
Tellurium is a chemical element with symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur.
Latin name: Tellurium
Atomic Number
52
Atomic Mass
127.6 g/mol
Phase (STP)
Solid
Electron Config.
[Kr] 4d¹⁰ 5s² 5p⁴
General
SymbolTe
Atomic Number52
Atomic Mass127.6 g/mol
CategoryMetalloid
Group16
Period5
Blockp-block
Electron Configuration[Kr] 4d¹⁰ 5s² 5p⁴
Valence Electrons6
Coloursilvery-white with bluish tinge
CAS NumberCAS13494-80-9
Physical Properties
Phase (STP)Solid
Density6.24 g/cm³
Melting Point449.51°C · 841.12°F · 722.66 K
Boiling Point987.85°C · 1810.13°F · 1261.00 K
Atomic Properties
Atomic Radius123 pm
Electronegativity2.1 Pauling
Ionization Energy869 kJ/mol
Oxidation States+6, +4, -2
Ion ChargeTe2-/Te4+/Te6+
Thermodynamic
Molar Heat25.73 J/(mol·K)
Crystal Structure
Crystal Structurehexagonal
Mechanical Properties
Mohs Hardness2.25
Nuclear & Hazards
Half-lifestable
Abundance
In Universe0.00007999999999999999%
In Sun0.00005%
In Earth's Crust0.00009999999999999999%
Discovery & History
Discovery Year1782
Discovered ByFranz-Joseph Müller von Reichenstein
Country of DiscoveryRomania
Isotopes of Tellurium
| Isotope | Abundance | Half-life | Decay |
|---|---|---|---|
| Te-120 | 0.09% | Stable | — |
| Te-122 | 2.55% | Stable | — |
| Te-123 | 0.89% | 9.2 × 10¹⁶ years | EC |
| Te-124 | 4.74% | Stable | — |
| Te-125 | 7.07% | Stable | — |
| Te-126 | 18.84% | Stable | — |
| Te-128 | 31.74% | 2.2 × 10²⁴ years | β⁻β⁻ |
| Te-130 | 34.08% | 8.2 × 10²⁰ years | β⁻β⁻ |