Tellurium (Te)
Metalloid
Tellurium is one of the rarest stable elements in the Earth's crust — rarer than platinum — yet it stars in rewritable DVDs, phase-change computer memory and CdTe solar panels.
Position on the periodic table
Atomic properties
| Atomic number | 52 |
|---|---|
| Atomic mass | 127.603 amu |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p4 |
| Noble gas shorthand | [Kr] 4d10 5s2 5p4 |
| Electrons per shell | 2, 8, 18, 18, 6 |
| Valence electrons (outer shell) | 6 |
| Common oxidation states | -2, +4, +6 |
| Electronegativity (Pauling) | 2.1 |
| Covalent radius (approx.) | 138 pm |
| First ionization energy | 869.3 kJ/mol |
| Electron affinity | 190.2 kJ/mol |
Physical properties
| State at 25 °C | Solid |
|---|---|
| Density | 6.24 g/cm³ |
| Melting point | 449.51 °C (722.66 K) |
| Boiling point | 987.85 °C (1261 K) |
| Appearance | Not available |
| Radioactive | No |
| Origin | Occurs naturally |
Electron configuration of tellurium
Tellurium's ground-state electron configuration is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p4, usually shortened to [Kr] 4d10 5s2 5p4. Its electrons occupy 5 shells (2, 8, 18, 18, 6), placing it in period 5 of the p-block. The 6 outer-shell electrons drive its bonding behaviour. Explore it interactively in the electron configuration calculator.
Uses of tellurium
- CdTe thin-film solar panels
- Phase-change optical discs and memory
- Thermoelectric coolers (bismuth telluride)
- Free-machining steel additive
Biological role: None known.
Occurrence: Extremely rare; recovered from copper-refining slimes.
Common compounds of tellurium
CdTe
Cadmium telluride
Bi2Te3
Bismuth telluride
History and discovery
Discovered: 1782 — Franz-Joseph Müller von Reichenstein. Name origin: From Latin tellus, meaning Earth.
Franz-Joseph Müller von Reichenstein discovered it in 1782 in gold ore from Transylvania.
Safety notes
Tellurium compounds are toxic; even small exposures cause the notorious garlic breath.
Educational context only — always follow your school's laboratory rules and never handle chemicals without proper supervision. See our disclaimer.
Practice questions
Quick practice: Tellurium
1. What is the chemical symbol of Tellurium?
2. What is the atomic number of Tellurium?
3. Which category does Tellurium belong to?
4. What is the state of Tellurium at room temperature?
5. Which period of the periodic table is Tellurium in?
Tellurium FAQs
What is the atomic number of tellurium?
Tellurium's atomic number is 52 — every tellurium atom has 52 protons in its nucleus.
What is the symbol for tellurium?
Te. From Latin tellus, meaning Earth.
Is tellurium a metal, nonmetal, or metalloid?
Tellurium is classified as a metalloid — an element with properties between metals and nonmetals.
What state is tellurium at room temperature?
At about 25 °C, tellurium is a solid. It melts at 449.51 °C.
How many valence electrons does tellurium have?
Tellurium has 6 electrons in its outer shell (shell pattern: 2, 8, 18, 18, 6).
What is tellurium used for?
Key uses include: cdte thin-film solar panels; phase-change optical discs and memory; thermoelectric coolers (bismuth telluride).
Related elements
Keep working with this element
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