Astat

85
At
Skupina
17
Perioda
6
Blok
p
Protoni
Elektroni
Neutroni
85
85
125
Opća svojstva
Atomski broj
85
Relativna atomska masa
[210]
Maseni broj
210
Kategorija
Halogeni elementi
Boja
Srebrna
Radioaktivan
Da
Od grčke riječi astatos, nestabilan
Kristalna struktura
n/a
Povijest
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.
Elektrona po ljusci
2, 8, 18, 32, 18, 7
Elektronska konfiguracija
[Xe] 4f14 5d10 6s2 6p5
At
Astatine is preferentially concentrated in the thyroid gland
Fizikalna svojstva
Agregacijsko stanje
Čvrsto
Gustoća
7 g/cm3
Talište
575,15 K | 302 °C | 575,6 °F
Vrelište
610,15 K | 337 °C | 638,6 °F
Toplina taljenja
6 kJ/mol
Toplina isparavanja
40 kJ/mol
Specifični toplinski kapacitet
-
Zastupljenost u Zemljinoj kori
n/a
Zastupljenost u svemiru
n/a
Emilio
Izvor slike: pauli.uni-muenster.de
Emilio Segrè, one of the discoverer of the element
CAS broj
7440-68-8
PubChem CID broj
n/a
Atomska svojstva
Atomski radijus
-
Kovalentni radijus
150 pm
Elektronegativnost
2,2 (Paulingova ljestvica)
Potencijal ionizacije
9,3 eV
Atomski volumen
30 cm3/mol
Toplinska vodljivost
0,017 W/cm·K
Stanja oksidacije
-1, 1, 3, 5, 7
Primjene
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
Izotopi
Stabilni izotopi
-
Nestabilni izotopi
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