No. Astatine is a nonmetal, classified as a halogen on the periodic table.

How many protons does astatine have?

Astatine has 85 protons. Its atomic number is 85, which is also the number of electrons in a neutral atom of astatine.

What group and period is astatine in?

Astatine is in group 17 and period 6 of the periodic table, in the p-block.

What is the atomic mass of astatine?

The atomic mass of astatine is 210 u (unified atomic mass units).

Element 85

Astatine (At)

Halogen · Period 6 · Group 17 · p-block

Astatine (At) is element 85 of the periodic table, a halogen in period 6, group 17 (p-block) with an atomic mass of 210 and is a solid at standard conditions.

At a glance

Atomic number: 85
Symbol: At
Atomic mass: 210 u
Category: Halogens
Period: 6
Group: 17
Block: p-block
Phase at STP: solid

Electron structure

Electron configuration: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 6s2 6p5
Shorthand configuration: [Xe] 4f14 5d10 6s2 6p5
Electrons per shell: 2, 8, 18, 32, 18, 7
Oxidation states: -1, +1, +3, +5, +7

Physical properties

Astatine is extremely rare and intensely radioactive, and no weighable sample has been isolated. The physical and atomic values below are estimates extrapolated from periodic trends, not direct measurements.

Melting point: 575 K (301.85 °C) (estimated)
Boiling point: 610 K (336.85 °C) (estimated)
Density: 7 g/cm³ (estimated)
Phase: solid

Atomic properties

Electronegativity (Pauling): 2.2 (estimated)
Atomic radius: 127 pm (estimated)
Covalent radius: 150 pm (estimated)
Van der Waals radius: 202 pm (estimated)
First ionization energy: 920 kJ/mol (estimated)
Electron affinity: 233 kJ/mol (estimated)

Notable isotopes

Notable isotopes of Astatine: mass number, atomic mass, natural abundance, and stability.
Isotope	Mass	Abundance	Stability
At-210	209.98715	-	Half-life 8.1 hours

Common uses

Cancer treatment research
Scientific research

Discovery

Year: 1940
Discovered by: Dale R. Corson, Kenneth Ross MacKenzie, Emilio Segrè
Country: USA

Frequently asked questions

Is astatine a metal?: No. Astatine is a nonmetal, classified as a halogen on the periodic table.
How many protons does astatine have?: Astatine has 85 protons. Its atomic number is 85, which is also the number of electrons in a neutral atom of astatine.
What group and period is astatine in?: Astatine is in group 17 and period 6 of the periodic table, in the p-block.
What is the atomic mass of astatine?: The atomic mass of astatine is 210 u (unified atomic mass units).

Keep exploring

Astatine's row is on the printable element property sheet, and its tile is on the periodic table wall chart - the same numbers as above, laid out for A4 or A3 paper.