Free Science Lessons: Group Zero Noble Gases

Introduction

• Objectives:
  • Describe the electronic structure of Group Zero noble gases.
  • Explain why Group Zero elements are unreactive.
  • Describe how boiling points of Group Zero elements vary down the group.

Overview of Group Zero

• Group Zero is known as the noble gases.
• Originally absent from the periodic table by Dimitri Mendeleev as they were discovered later.
• Key fact: Noble gases are very unreactive.

Electronic Structure and Reactivity

Helium

• First noble gas
• Structure: 2 electrons in the first energy level.
  • First energy level can hold a maximum of 2 electrons.
  • Full energy level = Stability
• Reactivity: Helium is stable and unreactive due to full outer energy level.

Neon

• Noble gas with 10 electrons.
• Structure:
  • 2 electrons in the first energy level.
  • 8 electrons in the second energy level (full).
• Reactivity: Neon is unreactive due to full outer energy level.

Argon

• Another noble gas
• Structure: 8 electrons in its outer energy level.
• Reactivity: Argon is unreactive due to full outer energy level.

General Rule

• All noble gases have a full outer energy level.
• This full outer energy level makes them unreactive.

Boiling Points and Trends

• Observation: Boiling points are lower than room temperature (all gases at room temp).
• Trend: Boiling points increase with increasing relative atomic mass (down Group Zero).
  • Helium: Lowest boiling point (relative atomic mass = 4).
  • Radon: Highest boiling point (relative atomic mass = 222).

Conclusion

• Noble gases are characterized by their full outer energy levels making them unreactive.
• Their boiling points vary with atomic mass, increasing as we move down the group.

Additional Resources:

• Revision workbook available for further questions on this topic.