Astatine
Table:
Astatine, 85At
Astatine
Pronunciation	/ˈæstətiːn, -tɪn/ ⓘ ​(ASS-tə-teen, -⁠tin)
Appearance	unknown, probably metallic
Mass number	[210]
Astatine in the periodic table

Hydrogen

Helium

Lithium

Beryllium

Boron

Carbon

Nitrogen

Oxygen

Fluorine

Neon

Sodium

Magnesium

Aluminium

Silicon

Phosphorus

Sulfur

Chlorine

Argon

Potassium

Calcium

Scandium

Titanium

Vanadium

Chromium

Manganese

Iron

Cobalt

Nickel

Copper

Zinc

Gallium

Germanium

Arsenic

Selenium

Bromine

Krypton

Rubidium

Strontium

Yttrium

Zirconium

Niobium

Molybdenum

Technetium

Ruthenium

Rhodium

Palladium

Silver

Cadmium

Indium

Tin

Antimony

Tellurium

Iodine

Xenon

Caesium

Barium

Lanthanum

Cerium

Praseodymium

Neodymium

Promethium

Samarium

Europium

Gadolinium

Terbium

Dysprosium

Holmium

Erbium

Thulium

Ytterbium

Lutetium

Hafnium

Tantalum

Tungsten

Rhenium

Osmium

Iridium

Platinum

Gold

Mercury (element)

Thallium

Lead

Bismuth

Polonium

Astatine

Radon

Francium

Radium

Actinium

Thorium

Protactinium

Uranium

Neptunium

Plutonium

Americium

Curium

Berkelium

Californium

Einsteinium

Fermium

Mendelevium

Nobelium

Lawrencium

Rutherfordium

Dubnium

Seaborgium

Bohrium

Hassium

Meitnerium

Darmstadtium

Roentgenium

Copernicium

Nihonium

Flerovium

Moscovium

Livermorium

Tennessine

Oganesson

I
↑
At
↓
Ts

polonium ← astatine → radon

Atomic number (Z)	85
Group	group 17 (halogens)
Period	period 6
Block	p-block
Electron configuration	[Xe] 4f14 5d10 6s2 6p5
Electrons per shell	2, 8, 18, 32, 18, 7
Physical properties
Phase at STP	solid (predicted)
Density (near r.t.)	8.91–8.95 g/cm3 (estimated)[1]
Molar volume	23.6 cm3/mol (estimated)[1]
Atomic properties
Oxidation states	common: −1, +1

+3,[2] +5,[2] +7[2]
Ionization energies

1st: 899.003 kJ/mol[3]

Other properties
Natural occurrence	from decay
Crystal structure	​face-centered cubic (fcc)

(predicted)[4]
CAS Number	7440-68-8
History
Naming	Ancient Greek ástatos (ἄστατος) 'unstable'
Discovery	Dale R. Corson, Kenneth Ross MacKenzie, Emilio Segrè (1940)
Isotopes of astatine

v
e

Main isotopes[5]

Decay

abun­dance

half-life (t1/2)

mode

pro­duct

207At

synth

1.80 h

β+91%

207Po

α8.60%

203Bi

208At

synth

1.63 h

β+99.5%

208Po

α0.55%

204Bi

209At

synth

5.41 h

β+96%

209Po

α4%

205Bi

210At

synth

8.1 h

β+99.8%

210Po

α0.180%

206Bi

211At

synth

7.21 h

ε58.2%

211Po

α42%

207Bi

Category: Astatine

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With reference to the table, identify if the claim is entailed, neutral, or refuted. Provide the verdict inside {"answer": "YOUR ANSWER"} as JSON.

Hypothesis: Astatine was discovered in the first-half of the 20th century by multiple people.

answer: entailed