Astatine (At)

General Information

• Symbol: At
• Atomic Number: 85
• Atomic Weight: [210] u (varies due to multiple isotopes)
• Element Category: Metalloid (sometimes classified as a halogen)
• Group: 17 (Halogens)
• Period: 6
• Block: p-block

Physical Properties

• Appearance: Unknown; likely a metallic appearance similar to iodine
• Density: Estimated around 7 g/cm³ (exact density unknown due to scarcity)
• Melting Point: Estimated around 302 °C (576 °F)
• Boiling Point: Estimated around 337 °C (639 °F)
• Phase at STP: Solid
• Electron Configuration: [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁵
• Oxidation States: +1, +3, +5, +7 (most common), -1

Chemical Properties

• Reactivity: Astatine is less reactive than other halogens and shows more metallic properties. It forms compounds with many elements, particularly hydrogen, halogens, and metals.
• Compounds: Forms compounds such as astatine hydride (AtH), astatine pentoxide (At₂O₅), and astatine chloride (AtCl).

Uses and Applications

• Medical Research: Used in targeted alpha-particle radiotherapy (TAT) for cancer treatment due to its radioactivity.
• Scientific Research: Studied for its chemical properties and behavior as a halogen and metalloid.
• Radiation Source: Used in research applications that require a radiation source.

Occurrence and Extraction

• Natural Occurrence: Found in trace amounts in uranium and thorium ores. It is the rarest naturally occurring halogen.
• Extraction: Typically produced synthetically by bombarding bismuth with alpha particles in a particle accelerator.

Isotopes

• Stable Isotopes: Astatine has no stable isotopes.
• Radioactive Isotopes: Several radioactive isotopes, including Astatine-210, Astatine-211 (used in medical research), Astatine-213, and Astatine-215.

Safety and Handling

• Hazards: Astatine is highly radioactive and poses severe health risks, including radiation sickness and increased cancer risk.
• Precautions: Handle with extreme caution using specialized protective equipment and facilities designed to contain radioactivity.

History

• Discovery: Discovered by Dale R. Corson, Kenneth Ross MacKenzie, and Emilio Segrè in 1940.
• Name Origin: Named from the Greek word “astatos,” meaning unstable, reflecting its radioactivity.

Additional Facts

• Crystal Structure: Unknown
• Magnetic Properties: Likely paramagnetic
• Thermal Conductivity: Unknown
• Electrical Resistivity: Unknown

Summary

Astatine is a highly radioactive and rare element classified as a metalloid or halogen. It has significant applications in medical research for targeted alpha-particle radiotherapy and is studied for its unique chemical properties. Found in trace amounts in uranium and thorium ores, astatine is typically produced synthetically. Discovered in 1940, its name reflects its instability. Due to its extreme radioactivity, astatine requires specialized handling and is primarily used in controlled research environments.

40 Question and Answer Pairs About Astatine

1. What is the atomic number of Astatine?

   • 85

2. What is the symbol for Astatine?

   • At

3. What is the atomic weight of Astatine?

   • [210] u (varies due to multiple isotopes)

4. In which group of the periodic table is Astatine found?

   • Group 17 (Halogens)

5. What period is Astatine in?

   • Period 6

6. What block does Astatine belong to?

   • p-block

7. What is the melting point of Astatine?

   • Estimated around 302 °C (576 °F)

8. What is the boiling point of Astatine?

   • Estimated around 337 °C (639 °F)

9. What is the density of Astatine?

   • Estimated around 7 g/cm³

10. What is the electron configuration of Astatine?

    • [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁵

11. What are the common oxidation states of Astatine?

    • +1, +3, +5, +7, -1

12. What is the appearance of Astatine?

    • Unknown; likely metallic similar to iodine

13. Is Astatine reactive with air?

    • Less reactive than other halogens; shows more metallic properties

14. Name a compound of Astatine.

    • Astatine hydride (AtH)

15. What is a common use of Astatine in medicine?

    • Used in targeted alpha-particle radiotherapy for cancer treatment

16. How is Astatine used in scientific research?

    • Studied for its chemical properties and behavior as a halogen and metalloid

17. What role does Astatine play as a radiation source?

    • Used in research applications requiring a radiation source

18. How is Astatine found in nature?

    • In trace amounts in uranium and thorium ores

19. How is Astatine typically produced?

    • By bombarding bismuth with alpha particles in a particle accelerator

20. What is the most common isotope of Astatine used in medical research?

    • Astatine-211

21. What safety hazard is associated with Astatine?

    • Highly radioactive and poses severe health risks

22. Who discovered Astatine?

    • Dale R. Corson, Kenneth Ross MacKenzie, and Emilio Segrè

23. Where does the name Astatine come from?

    • From the Greek word “astatos,” meaning unstable

24. What is the crystal structure of Astatine?

    • Unknown

25. Is Astatine paramagnetic or diamagnetic?

    • Likely paramagnetic

26. What is the thermal conductivity of Astatine?

    • Unknown

27. What is the electrical resistivity of Astatine?

    • Unknown

28. What is the primary oxidation state of Astatine?

    • +1, +3, +5, +7

29. Is Astatine found as a free element in nature?

    • No, it is found in trace amounts in uranium and thorium ores

30. What is the common name of Astatine chloride?

    • AtCl

31. What is a major application of Astatine pentoxide (At₂O₅)?

    • Used in scientific research

32. How does Astatine benefit medical research?

    • Used in targeted alpha-particle radiotherapy for cancer treatment

33. What is the boiling point of Astatine in Kelvin?

    • Estimated around 610 K

34. What group does Astatine belong to in the periodic table?

    • Group 17 (Halogens)

35. What is the natural abundance of Astatine-210?

    • Extremely rare and mostly synthetic

36. Can Astatine be used in high-temperature applications?

    • Yes, but it is highly radioactive

37. What is the key property that makes Astatine valuable in neutron sources?

    • Emits alpha particles

38. How is Astatine used in radiation research?

    • As a radiation source in various experiments

39. What precautions should be taken when handling Astatine?

    • Use specialized protective equipment and facilities designed to contain radioactivity

40. What makes Astatine unique among the elements?

    • Its extreme radioactivity and its rare occurrence in nature.