Astat

85
At
Gruppe
17
Periode
6
Blok
p
Protons
Electrons
Neutrons
85
85
125
General Properties
Atomnummer
85
Atommasse
[210]
Mass Number
210
Kategori
Halogener
Farve
Silver
Radioactive
Ja
From the Greek astatos meaning unstable
Krystalstruktur
n/a
History
In 1869, existence of astatine was first predicted by Russian chemist Dmitri Mendeleev and called the element eka-iodine.

In 1940, Dale R. Corson, Kenneth Ross MacKenzie, and Emilio Segrè isolated the element at the University of California, Berkeley.

Instead of searching for the element in nature, the scientists created it by bombarding bismuth-209 with alpha particles.
Elektroner i hver skal
2, 8, 18, 32, 18, 7
Elektronkonfiguration
[Xe] 4f14 5d10 6s2 6p5
At
Astatine is preferentially concentrated in the thyroid gland
Physical Properties
Tilstandsform
Fast stof
Massefylde
7 g/cm3
Smeltepunkt
575,15 K | 302 °C | 575,6 °F
Kogepunkt
610,15 K | 337 °C | 638,6 °F
Smeltevarme
6 kJ/mol
Fordampningsvarme
40 kJ/mol
Varmefylde
-
Abundance in Earth's crust
n/a
Abundance in Universe
n/a
Emilio
Billede akkrediteringer: pauli.uni-muenster.de
Emilio Segrè, one of the discoverer of the element
CAS Number
7440-68-8
PubChem CID Number
n/a
Atomic Properties
Atomradius
-
Kovalent radius
150 pm
Elektronegativitet
2,2 (Paulings skala)
Ionization Potential
9,3 eV
Atomic Volume
30 cm3/mol
Varmeledningsevne
0,017 W/cm·K
Oxidationstrin
-1, 1, 3, 5, 7
Applications
The newly formed astatine-211 is important in nuclear medicine.

Once produced, astatine must be used quickly, as it decays with a half-life of 7.2 hours.

Astatine-211 can be used for targeted alpha particle radiotherapy, since it decays either via emission of an alpha particle.
Astatine is highly radioactive
Isotoper
Stable Isotopes
-
Unstable Isotopes
193At, 194At, 195At, 196At, 197At, 198At, 199At, 200At, 201At, 202At, 203At, 204At, 205At, 206At, 207At, 208At, 209At, 210At, 211At, 212At, 213At, 214At, 215At, 216At, 217At, 218At, 219At, 220At, 221At, 222At, 223At