Gallium: Element Overview

Basic Information

• Symbol: Ga
• Atomic Number: 31
• Atomic Weight: 69.723 u
• Element Category: Post-transition metal
• Group: 13
• Period: 4

Physical Properties

• Phase at Room Temperature: Solid
• Melting Point: 29.76 °C (85.57 °F) – Gallium is one of the few metals that can melt in the palm of your hand.
• Boiling Point: 2204 °C (3999 °F)
• Density: 5.91 g/cm³ at 25 °C
• Color: Silvery blue
• Crystal Structure: Orthorhombic

Chemical Properties

• Electronegativity: 1.81 (Pauling scale)
• Ionization Energies:
  • First: 578.8 kJ/mol
  • Second: 1979.3 kJ/mol
  • Third: 2963 kJ/mol
• Oxidation States: +3 (most common), +2, +1
• Reactivity: Reacts with both acids and alkalis. Stable in dry air, but forms a protective oxide layer in moist air.

Isotopes

• Stable Isotopes: Gallium has two stable isotopes: Ga-69 and Ga-71.
  • Ga-69: 60.11%
  • Ga-71: 39.89%
• Radioisotopes: Several radioisotopes, including Ga-67, which is used in medical diagnostic procedures.

Occurrence and Production

• Natural Abundance: Gallium is the 34th most abundant element in the Earth’s crust.
• Sources: Found in trace amounts in bauxite and zinc ores. Also found in minerals like gallite (CuGaS₂).
• Production: Obtained primarily as a byproduct of aluminum and zinc production through the extraction from bauxite ore and sphalerite.

Uses and Applications

• Electronics: Used in semiconductors, particularly gallium arsenide (GaAs), which is used in light-emitting diodes (LEDs), solar cells, and high-speed electronics.
• Thermometers: Used in high-temperature thermometers and barometers as a non-toxic alternative to mercury.
• Alloys: Used to create low-melting alloys, such as galinstan (gallium, indium, and tin), which is a mercury substitute in thermometers.
• Medical: Gallium-67 is used as a radiotracer in nuclear medicine.
• Research: Used in various scientific applications and research due to its unique properties.

Safety and Precautions

• Reactivity: Gallium is relatively non-reactive and safe to handle in small amounts. However, it should be stored in containers that do not react with it, as it can attack other metals.
• Handling: Generally safe to handle, but caution should be exercised when dealing with its compounds, which can be toxic.
• Toxicity: Gallium is considered to have low toxicity, but gallium compounds should be handled with care to avoid ingestion and inhalation.

Biological Role

• Non-essential Element: Gallium has no known biological role and is not essential for life.
• Medical Use: Used in medical imaging and cancer treatment due to its ability to bind with transferrin, a protein that transports iron in the body.

Historical Background

• Discovery: Discovered by French chemist Paul-Émile Lecoq de Boisbaudran in 1875.
• Naming: Named after “Gallia,” the Latin name for France.

Interesting Facts

• Low Melting Point: Gallium’s melting point is so low that it can melt in your hand, making it unique among metals.
• Expands on Freezing: Unlike most metals, gallium expands when it solidifies, which can cause containers to break if filled with liquid gallium and then frozen.
• Galinstan: An alloy of gallium, indium, and tin, is liquid at room temperature and used as a non-toxic alternative to mercury.

Summary

Gallium is a unique post-transition metal known for its low melting point and application in electronics, thermometers, and medical imaging. Discovered in the late 19th century, gallium is primarily obtained as a byproduct of aluminum and zinc production. Its non-toxic nature and ability to form alloys make it valuable in various industrial and scientific applications. While not essential for life, gallium’s properties continue to be explored for innovative uses in technology and medicine.

Questions and Answers about Gallium:

1. Q: What is the chemical symbol for Gallium?

   • A: Ga

2. Q: What is the atomic number of Gallium?

   • A: 31

3. Q: What type of element is Gallium?

   • A: Post-transition metal

4. Q: What is the atomic weight of Gallium?

   • A: 69.723 u

5. Q: What group is Gallium in?

   • A: Group 13

6. Q: What period is Gallium in?

   • A: Period 4

7. Q: What is the phase of Gallium at room temperature?

   • A: Solid

8. Q: What is the melting point of Gallium?

   • A: 29.76 °C (85.57 °F)

9. Q: What is the boiling point of Gallium?

   • A: 2204 °C (3999 °F)

10. Q: What is the density of Gallium at 25 °C?

    • A: 5.91 g/cm³

11. Q: What is the color of Gallium metal?

    • A: Silvery blue

12. Q: What is the crystal structure of Gallium?

    • A: Orthorhombic

13. Q: What is the electronegativity of Gallium?

    • A: 1.81 (Pauling scale)

14. Q: What is the first ionization energy of Gallium?

    • A: 578.8 kJ/mol

15. Q: How many stable isotopes does Gallium have?

    • A: Two (Ga-69, Ga-71)

16. Q: What is the most abundant isotope of Gallium?

    • A: Ga-69

17. Q: How is Gallium commercially produced?

    • A: As a byproduct of aluminum and zinc production through extraction from bauxite ore and sphalerite

18. Q: What is the natural abundance of Gallium in the Earth’s crust?

    • A: 34th most abundant element

19. Q: What common minerals contain Gallium?

    • A: Bauxite, zinc ores, gallite (CuGaS₂)

20. Q: What industry uses Gallium extensively for semiconductors?

    • A: Electronics industry

21. Q: What is one use of Gallium in the medical field?

    • A: Used as a radiotracer in nuclear medicine (Ga-67)

22. Q: What role does Gallium play in the production of LEDs?

    • A: Used in gallium arsenide (GaAs) for light-emitting diodes

23. Q: Why is Gallium used in high-temperature thermometers?

    • A: Because of its high boiling point and non-toxic nature

24. Q: What is the biological role of Gallium in the body?

    • A: Gallium has no known biological role and is not essential for life

25. Q: Who discovered Gallium?

    • A: Paul-Émile Lecoq de Boisbaudran

26. Q: In what year was Gallium discovered?

    • A: 1875

27. Q: What is the origin of the name “Gallium”?

    • A: Named after “Gallia,” the Latin name for France

28. Q: What property makes Gallium unique among metals?

    • A: Its low melting point, which allows it to melt in the palm of your hand

29. Q: What health hazard is associated with Gallium compounds?

    • A: Gallium compounds can be toxic and should be handled with care

30. Q: How should Gallium be stored?

    • A: In containers that do not react with it, as it can attack other metals

31. Q: What is the second ionization energy of Gallium?

    • A: 1979.3 kJ/mol

32. Q: What is the third ionization energy of Gallium?

    • A: 2963 kJ/mol

33. Q: Is Gallium essential for plant health?

    • A: Gallium is not essential for plant health

34. Q: What is the significance of Gallium in scientific research?

    • A: Used in various scientific applications due to its unique properties

35. Q: What is the role of Gallium in the production of galinstan?

    • A: Combined with indium and tin to make a low-melting alloy used as a mercury substitute

36. Q: How does Gallium benefit the electronics industry?

    • A: Used in semiconductors and high-speed electronics

37. Q: What is Gallium’s role in cancer treatment?

    • A: Used in medical imaging and cancer treatment due to its ability to bind with transferrin

38. Q: What is the use of Gallium in high-temperature thermometers?

    • A: Used as a non-toxic alternative to mercury

39. Q: What is the environmental impact of Gallium mining?

    • A: Generally low, as it is primarily a byproduct of aluminum and zinc production

40. Q: What color are Gallium compounds typically?

    • A: They can exhibit various colors, with some compounds being colorless