85 At
Halogen
Astatine
Rarest natural element.
Properties of Astatine
- Atomic number (Z)
- 85
- Symbol
- At
- Atomic mass
- 210 g/mol
- Category
- Halogen
- Group
- 17
- Period
- 6
- Electron configuration
- [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁵
- Electronegativity (Pauling)
- 2.2
- Atomic radius
- 127 pm
- First ionization energy
- 899 kJ/mol
- Melting point
- 575 K (301.9 °C)
- Boiling point
- 610 K (336.9 °C)
- Density
- 6.35 g/cm³
- Phase at 25 °C
- Solid
- Discovered
- Discovered in 1940
Frequently asked questions
What is Astatine?
Astatine (At) is a halogen, element number 85 on the periodic table. Rarest natural element.
What is the atomic number and atomic mass of Astatine?
Astatine has atomic number 85 and an atomic mass of about 210 g/mol.
What is the electron configuration of Astatine?
The electron configuration of Astatine is [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁵.
Where is Astatine on the periodic table?
Astatine sits in group 17, period 6, and is classified as a halogen.