Cadmium (Cd)

General Information

• Symbol: Cd
• Atomic Number: 48
• Atomic Weight: 112.414 u
• Element Category: Transition metal
• Group: 12
• Period: 5
• Block: d-block

Physical Properties

• Appearance: Silvery-blue metallic
• Density: 8.65 g/cm³
• Melting Point: 321.07 °C (609.93 °F)
• Boiling Point: 767 °C (1413 °F)
• Phase at STP: Solid
• Electron Configuration: [Kr] 4d¹⁰ 5s²
• Oxidation States: +2 (most common), +1

Chemical Properties

• Reactivity: Relatively low reactivity; does not tarnish in air but forms a layer of cadmium oxide (CdO).
• Compounds: Forms compounds such as cadmium sulfide (CdS), cadmium oxide (CdO), and cadmium chloride (CdCl₂).

Uses and Applications

• Batteries: Used in nickel-cadmium (NiCd) rechargeable batteries.
• Pigments: Used in cadmium pigments such as cadmium yellow (CdS) and cadmium red (CdSe).
• Electroplating: Used in electroplating to provide a corrosion-resistant layer.
• Nuclear Reactors: Used as a neutron absorber in control rods.
• Alloys: Combined with other metals to form low-melting alloys for soldering and brazing.

Occurrence and Extraction

• Natural Occurrence: Found in zinc ores such as sphalerite (ZnS) and also in greenockite (CdS).
• Extraction: Extracted as a byproduct of zinc refining through processes involving roasting, reduction, and purification.

Isotopes

• Stable Isotopes: Cadmium-106, Cadmium-108, Cadmium-110, Cadmium-111, Cadmium-112, Cadmium-113, Cadmium-114, Cadmium-116
• Radioactive Isotopes: Cadmium-109, Cadmium-115m (used in nuclear and medical applications)

Safety and Handling

• Hazards: Highly toxic, carcinogenic; exposure can lead to serious health issues such as kidney damage, bone disease, and respiratory problems.
• Precautions: Handle with care, using appropriate protective equipment and following safety protocols to avoid inhalation, ingestion, and skin contact.

History

• Discovery: Discovered by Friedrich Stromeyer in 1817.
• Name Origin: Named after the Latin word “cadmia,” meaning calamine (zinc carbonate).

Additional Facts

• Crystal Structure: Hexagonal close-packed (hcp)
• Magnetic Properties: Diamagnetic
• Thermal Conductivity: Moderate, about 96.6 W/m·K
• Electrical Resistivity: About 72.7 nΩ·m at room temperature

Summary

Cadmium is a transition metal known for its use in rechargeable batteries, pigments, electroplating, and nuclear reactors. It is extracted as a byproduct of zinc refining and has several stable isotopes. Despite its useful applications, cadmium is highly toxic and requires careful handling to avoid health risks.

40 Question and Answer Pairs About Cadmium

1. What is the atomic number of Cadmium?

   • 48

2. What is the symbol for Cadmium?

   • Cd

3. What is the atomic weight of Cadmium?

   • 112.414 u

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

   • Group 12

5. What period is Cadmium in?

   • Period 5

6. What block does Cadmium belong to?

   • d-block

7. What is the melting point of Cadmium?

   • 321.07 °C (609.93 °F)

8. What is the boiling point of Cadmium?

   • 767 °C (1413 °F)

9. What is the density of Cadmium?

   • 8.65 g/cm³

10. What is the electron configuration of Cadmium?

    • [Kr] 4d¹⁰ 5s²

11. What are the common oxidation states of Cadmium?

    • +2, +1

12. What is the appearance of Cadmium?

    • Silvery-blue metallic

13. Does Cadmium tarnish in air?

    • No, it forms a layer of cadmium oxide (CdO)

14. Name a compound of Cadmium.

    • Cadmium sulfide (CdS)

15. What is a common use of Cadmium in batteries?

    • In nickel-cadmium (NiCd) rechargeable batteries

16. How is Cadmium used in pigments?

    • In cadmium yellow (CdS) and cadmium red (CdSe)

17. What role does Cadmium play in electroplating?

    • Provides a corrosion-resistant layer

18. How is Cadmium used in nuclear reactors?

    • As a neutron absorber in control rods

19. What application does Cadmium have in alloys?

    • Combined with other metals for soldering and brazing

20. Name a mineral that contains Cadmium.

    • Sphalerite (ZnS)

21. How is Cadmium extracted from ores?

    • As a byproduct of zinc refining through roasting, reduction, and purification

22. What is the most stable isotope of Cadmium?

    • Cadmium-112

23. Name a radioactive isotope of Cadmium used in applications.

    • Cadmium-109

24. What safety hazard is associated with Cadmium?

    • Highly toxic and carcinogenic

25. Who discovered Cadmium?

    • Friedrich Stromeyer

26. Where does the name Cadmium come from?

    • From the Latin word “cadmia,” meaning calamine

27. What is the crystal structure of Cadmium?

    • Hexagonal close-packed (hcp)

28. Is Cadmium paramagnetic or diamagnetic?

    • Diamagnetic

29. What is the thermal conductivity of Cadmium?

    • About 96.6 W/m·K

30. What is the electrical resistivity of Cadmium at room temperature?

    • About 72.7 nΩ·m

31. What is the primary oxidation state of Cadmium?

    • +2

32. Is Cadmium found as a free element in nature?

    • No, it is found in ores with other metals

33. What is the common name of cadmium chloride?

    • CdCl₂

34. What is a major application of cadmium oxide (CdO)?

    • Used in electroplating and as a stabilizer in plastics

35. How does Cadmium benefit pigments?

    • Provides vibrant colors such as yellow and red

36. What is the boiling point of Cadmium in Kelvin?

    • 1040 K

37. What group does Cadmium belong to in the periodic table?

    • Transition metals

38. What is the natural abundance of Cadmium-112?

    • About 24.13%

39. Can Cadmium be used in high-temperature applications?

    • Yes, in specific low-melting alloys

40. What is the key property that makes Cadmium valuable in batteries?

    • Its ability to undergo multiple charge-discharge cycles.