Астат

85
At
Група
17
Периода
6
блок
p
Protons
Electrons
Neutrons
85
85
125
Општи Својства
Атомски број
85
Атомска тежина
[210]
Mass Number
210
Category
Халогени
Color
Silver
Radioactive
Да
From the Greek astatos meaning unstable
Кристална структура
Нема одговор
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.
Electrons per shell
2, 8, 18, 32, 18, 7
Електронска конфигурација
[Xe] 4f14 5d10 6s2 6p5
At
Astatine is preferentially concentrated in the thyroid gland
Физички Својства
Фаза
Solid
Густина
7 g/cm3
Точка на топење
575,15 K | 302 °C | 575,6 °F
Точка на вриење
610,15 K | 337 °C | 638,6 °F
Топлина на топење
6 kJ/mol
Топлина на испарување
40 kJ/mol
Specific Heat Capacity
-
Abundance in Earth's crust
Нема одговор
Abundance in Universe
Нема одговор
Emilio
Кредити на слика: pauli.uni-muenster.de
Emilio Segrè, one of the discoverer of the element
CAS Number
7440-68-8
PubChem CID Number
Нема одговор
Атомски Својства
Атомски полупречник
-
Ковалентен полупречник
150 pm
Електронегативност
2,2 (Полингова скала)
Ionization Potential
9,3 eV
Atomic Volume
30 cm3/mol
Thermal Conductivity
0,017 W/cm·K
Oxidation States
-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
Isotopes
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