Lecture Notes: Noble Gases

Introduction to Noble Gases

• Location on Periodic Table: Found on the right hand side.
• Group Name: Known as Group 0 or Group 8 elements.
• Elements Included:
  • Helium
  • Neon
  • Argon
  • Krypton
  • Xenon
  • Radon

Properties of Noble Gases

• Nature: Non-metallic and monatomic (exist as single atoms).
• Physical Properties:
  • Colourless gases
  • Low melting points
  • Low boiling points
• Chemical Properties:
  • Unreactive (chemically inert)
  • Do not form molecules easily

Reason for Unreactivity

• Electronic Configuration:
  • Helium: 2 electrons in the first shell (full)
  • Neon: 10 electrons (2 in first shell, 8 in second shell)
  • Argon: 18 electrons (2 in first shell, 8 in second, 8 in third shell)
• Full Outer Shell:
  • Most noble gases have 8 electrons in the outer shell.
  • Helium has 2 electrons in its outer shell.
• Stability: Full outer shell is a stable configuration, leading to non-reactivity.

Exam Preparation

• Exam Questions:
  • Focus on reactivity of noble gases, e.g., xenon.
  • Key Points for Answers:
    • State that noble gases like xenon are unreactive.
    • Explain unreactivity due to full outer electron shell.
  • Use terms like "stable electron arrangement" or "eight electrons in outer shell".

Applications

• Noble Gases in Applications:
  • Chosen for their unreactivity.
  • Example: Argon in light bulbs.
    • Reason: Argon doesn't react with tungsten wire.
    • Comparison: Air would lead to oxidation of tungsten due to oxygen presence.

Summary

• Noble gases are non-metals, monatomic, and unreactive.
• Full outer electron shells contribute to their stability.
• Helium is an exception with 2 electrons in its outer shell.
• When discussing applications, always link property (e.g., unreactivity) to practical use.

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