85
At
Astatine
Astatine
Astatine (At)
Halogens · Solid · Period 6 · Group 17
Element Properties
- Atomic Number
- 85
- Symbol
- At
- Atomic Mass
- 209.9872
- Category
- Halogens
- Standard State
- Solid
- Period
- 6
- Group
- 17
- Electronegativity
- 2.2
- Atomic Radius
- 202
- Ionization Energy
- 9.5
- Electron Affinity
- 2.8
- Oxidation States
- 7, 5, 3, 1, -1
- Melting Point
- 575 K (301.85 °C)
- Boiling Point
- —
- Density
- 7
- Electron Configuration
- [Xe]6s2 4f14 5d10 6p5
- Year Discovered
- 1940
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Frequently asked questions
What is the atomic number of Astatine?
The atomic number of Astatine is 85, which equals the number of protons in its nucleus.
What is the atomic mass of Astatine?
The atomic mass of Astatine is approximately 209.9872 u (one twelfth of the mass of a carbon-12 atom).
What is the electron configuration of Astatine?
The electron configuration of Astatine is [Xe]6s2 4f14 5d10 6p5.
Where is Astatine in the periodic table?
Astatine is located in period 6, group 17.
When was Astatine discovered?
Astatine was discovered in 1940.
Related elements
Same group
9
F
Fluorine
18.998
17
Cl
Chlorine
35.45
35
Br
Bromine
79.9
53
I
Iodine
126.904
117
Ts
Tennessine
294.211