85 - Astatine metalloid
Discovered by Dale R. Corson in 1940
- Atomic Radius (Å)
Astatine is a very rare radioactive chemical element with the chemical symbol At and atomic number 85. It occurs on Earth as the decay product of various heavier elements. All its isotopes are short-lived; the most stable is astatine-210, with a half-life of 8.1 hours.
Shell | Electrons | Orbitals |
---|---|---|
1 | 2 | 2 in 1s |
2 | 8 | 2 in 2s + 6 in 2p |
3 | 18 | 2 in 3s + 6 in 3p + 10 in 3d |
4 | 32 | 2 in 4s + 6 in 4p + 10 in 4d + 14 in 4f |
5 | 18 | 2 in 5s + 6 in 5p + 10 in 5d |
6 | 7 | 2 in 6s + 5 in 6p |
210 u
Atomic Mass
1.4 Å
Atomic Radius
610 K
Boiling Point
1.5 Å
Covalent Radius
6.35 g/cm³
Density
233
Electron Affinity
2.2
Electronegativity
9.3 eV
First Ionization Energy
575.15 K
Melting Point
6
Number of Shells
7
Electron Valency
85
Atomic Number