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Astatine
العنصر 85 · 209.98715 u
Astatine is the rarest naturally occurring element on Earth.
Physical Properties
| الكتلة الذرية | 209.98715 u |
| الكثافة | 7.0 g/cm³ |
| Melting Point | 575.0 K |
| نقطة الغليان | 610.0 K |
| المظهر | Likely metallic |
| State at Room Temp | Solid |
الخواص الكيميائية
| السالبية الكهربائية | 2.2 (Pauling) |
| طاقة التأين الأولى | 899.0 kJ/mol |
| القرب الإلكتروني | 270.1 kJ/mol |
| Oxidation States | -1, +1, +3, +5, +7 |
الخصائص الذرية
| تشكيل الإلكترون | [Xe] 4f14 5d10 6s2 6p5 |
| نصف قطر الذرة | 150.0 pm |
| نصف قطر التكافؤ | 150.0 pm |
| Van der Waals Radius | 202.0 pm |
اكتشاف
| اكتشفها | Dale R. Corson, Kenneth Ross MacKenzie, Emilio Segre |
| سنة الاكتشاف | 1940 |
| الموقع | Berkeley, California, USA |
| Named After | Greek 'astatos' meaning unstable |
عن Astatine
Astatine is extremely rare, radioactive, and the heaviest known halogen. Less than 30 grams exist in Earth's crust at any time. It has never been seen in bulk.
Uses & Applications
Potential targeted cancer therapy (astatine-211), still experimental.
حقيقة مضحكة
Astatine has never been seen with the naked eye -- there is less than 30 grams in the entire Earth at any moment.
النظائر
| Mass Number | الوفرة | نصف العمر | Stable |
| 209 | - | 5.41 hours | No |
| 210 | - | 8.1 hours | No |
| 211 | - | 7.214 hours | No |
تشكيل الإلكترون
[Xe] 4f14 5d10 6s2 6p5