85 - Astatine metalloid
Discovered by Dale R. Corson in 1940
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.
Periodic table
| 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 |
Electron shells
probably metallic Appearance
210 u Atomic Mass
610 K Boiling Point
17 Group
-1, 1 Common Oxidation States
1.5 Å Covalent Radius
6.35 g/cm³ Density
233 kJ/mol Electron Affinity
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p5 Electron Configuration
[Xe] 4f14 5d10 6s2 6p5 Electron Configuration (semantic)
2.2 Electronegativity
85 Electrons
9.3 eV First Ionization Energy
899.003 kJ/mol Ionization Energies
575 K Melting Point
96 Mendeleev Number
6 Number of Shells
7 Electron Valency
125 Neutrons
85 Atomic Number
21 Number of Isotopes
-1, 1, 3, 5 Oxidation States
6 Period
Solid Phase
85 Protons
2, 8, 18, 32, 18, 7 Electron Shell Occupations