Curium (Cm)

General Information

• Symbol: Cm
• Atomic Number: 96
• Atomic Weight: 247 u
• Element Category: Actinide
• Group: N/A (Actinides series)
• Period: 7
• Block: f-block

Physical Properties

• Appearance: Silvery metallic, tarnishes in air
• Density: 13.51 g/cm³
• Melting Point: 1340 °C (2444 °F)
• Boiling Point: 3110 °C (5630 °F)
• Phase at STP: Solid
• Electron Configuration: [Rn] 5f⁷ 6d¹ 7s²
• Oxidation States: +3 (most common), +4

Chemical Properties

• Reactivity: Curium is reactive and forms various compounds, primarily in the +3 oxidation state. It reacts with oxygen, water, and acids.
• Compounds: Forms compounds such as curium dioxide (CmO₂), curium(III) chloride (CmCl₃), and curium(III) nitrate (Cm(NO₃)₃).

Uses and Applications

• Radioisotope Thermoelectric Generators (RTGs): Curium-244 and Curium-242 are used as heat sources in RTGs for space missions and remote power sources.
• Research: Used in scientific research to understand the properties of transuranic elements.
• Neutron Sources: Curium-244 is used as a neutron source in various applications.

Occurrence and Extraction

• Natural Occurrence: Curium does not occur naturally and is a synthetic element.
• Production: Produced in nuclear reactors by bombarding plutonium or uranium with neutrons.

Isotopes

• Stable Isotopes: Curium has no stable isotopes.
• Radioactive Isotopes: The most common isotopes are Curium-244 (half-life of 18.1 years), Curium-242 (half-life of 162.8 days), and Curium-247 (half-life of 15.6 million years).

Safety and Handling

• Hazards: Curium is highly radioactive and poses significant health risks. It can cause radiation poisoning and cancer if inhaled or ingested.
• Precautions: Handle with extreme care, using appropriate protective equipment and working in controlled environments. Proper disposal of radioactive materials is crucial.

History

• Discovery: Discovered by Glenn T. Seaborg, Albert Ghiorso, and James in 1944.
• Name Origin: Named after Marie and Pierre Curie, pioneers in the field of radioactivity.

Additional Facts

• Crystal Structure: Double hexagonal close-packed (dhcp)
• Magnetic Properties: Paramagnetic
• Thermal Conductivity: 10 W/m·K
• Electrical Resistivity: 125 µΩ·cm at 25°C

Summary

Curium is a synthetic element used primarily in RTGs, scientific research, and as a neutron source. Discovered in 1944, it is produced in nuclear reactors and requires careful handling due to its high radioactivity.

40 Question and Answer Pairs About Curium

1. What is the atomic number of Curium?

   • 96

2. What is the symbol for Curium?

   • Cm

3. What is the atomic weight of Curium?

   • 247 u

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

   • Actinides series (no specific group)

5. What period is Curium in?

   • Period 7

6. What block does Curium belong to?

   • f-block

7. What is the density of Curium?

   • 13.51 g/cm³

8. What is the melting point of Curium?

   • 1340 °C (2444 °F)

9. What is the boiling point of Curium?

   • 3110 °C (5630 °F)

10. What is the electron configuration of Curium?

    • [Rn] 5f⁷ 6d¹ 7s²

11. What are the common oxidation states of Curium?

    • +3 (most common), +4

12. What is the appearance of Curium?

    • Silvery metallic

13. Is Curium reactive with air?

    • Yes, it tarnishes in air.

14. Name a compound of Curium.

    • Curium dioxide (CmO₂)

15. What is a common use of Curium-244?

    • Used in RTGs for space missions.

16. How is Curium used in scientific research?

    • To study the properties of transuranic elements.

17. What role does Curium play as a neutron source?

    • Curium-244 is used in various neutron source applications.

18. How is Curium typically produced?

    • By bombarding plutonium or uranium with neutrons in nuclear reactors.

19. What is the most common isotope of Curium for RTGs?

    • Curium-244

20. How is Curium extracted?

    • Produced synthetically in nuclear reactors.

21. What safety hazard is associated with Curium dust?

    • It is highly radioactive and poses significant health risks.

22. Who discovered Curium?

    • Glenn T. Seaborg, Albert Ghiorso, and James

23. Where does the name Curium come from?

    • Named after Marie and Pierre Curie.

24. What is the crystal structure of Curium at room temperature?

    • Double hexagonal close-packed (dhcp)

25. Is Curium paramagnetic or diamagnetic at room temperature?

    • Paramagnetic

26. What is the thermal conductivity of Curium?

    • 10 W/m·K

27. What is the electrical resistivity of Curium at 25°C?

    • 125 µΩ·cm

28. What is the primary oxidation state of Curium in its compounds?

    • +3

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

    • No, it is a synthetic element.

30. What is the common name of Curium(III) chloride?

    • CmCl₃

31. What is a major application of Curium in space technology?

    • Used in RTGs for power generation.

32. How does Curium benefit scientific research?

    • Used to study transuranic elements.

33. What is the melting point of Curium in Kelvin?

    • 1613 K

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

    • Actinides series

35. What is the natural abundance of Curium-244?

    • It is produced synthetically and is not found naturally.

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

    • Yes, particularly in RTGs for space missions.

37. What is the key property that makes Curium valuable in RTGs?

    • Its ability to generate heat.

38. How is Curium used in the chemical industry?

    • Mainly in research and specialized applications.

39. What precautions should be taken when handling Curium?

    • Use appropriate protective equipment to avoid inhalation or ingestion.

40. What are the health risks associated with Curium?

    • It can cause radiation poisoning and cancer if inhaled or ingested.