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Element 52 - Tellurium (Te) sound

From tellus, the earth; discovered 1782. With both metallic and non-metallic traits, tellurium has several peculiarities. It is "out of step" in the periodic table, having a lower atomic number but higher atomic weight than iodine. And inhaling its vapour results in garlicky breath.

Properties

Atomic Number: 52
Atomic Weight: 127.60
Electron Configuration (at ground state): 1s22s22p63s23p63d104s24p64d105s25p4
Oxidation States (Bold most stable): -2, +4, +6
Boiling Point (K): 1261
Melting Point (K): 722.72
Density (at 300K -- g/cm3): 6.24
Atomic Volume (at 300K -- cm3/mol) 20.50
Number of stable isotopes: 8
Mass Number (Bold naturally occurring) -- Half-Life -- Disintigration Type: 121 -- 154 days -- isomeric transition from upper to lower isomeric state
123 -- 119.7 days -- isomeric transition from upper to lower isomeric state
127 -- 109 days -- isomeric transition from upper to lower isomeric state
Covalent Radius (Å): 1.36
Atomic Radius (Å): 1.42
First Ionization Potential (V): 9.009
Electronegativity (Pauling's): 2.1
Specific Heat Capacity (at 300K -- J g-1 K-1): 0.202
Heat of Vaporization (kJ/mol): 50.63
Heat of Fusion (kJ/mol): 17.49
Electrical Conductivity (at 293K for polycrystalline material -- 106 (ohms)-1 cm-1): 2 x 10-4
Thermal Conductivity (at 300K -- W m-1 K-1): 2.35
Crystal Structure: Hexagonal
Acid-Base Properties: Slightly acidic