Halogen

Astatine

Astatine (At) has atomic number 85. PubChem classifies it as halogen.

Atomic number

85

Symbol

At

Atomic weight (source value)

209.98715

Electron configuration

[Xe]6s2 4f14 5d10 6p5

Standard state

Solid

Electronegativity (Pauling)

2.2

Melting point (K)

575

Boiling point (K)

Not provided

Density (g/cm³)

7

Oxidation states

7, 5, 3, 1, -1

Understanding this entry

Atomic number is the number of protons in the nucleus. Properties are reference values and may depend on conditions and measurement conventions. An atomic weight is not the mass of every isotope. For elements without a standard atomic weight, a source may report an isotope mass number. Blank source values are shown as unavailable rather than estimated.

Further reading and reference: NIH PubChem source dataset ↗. Values and educational summaries are not a substitute for specialised advice.