Free Science Lessons: Noble Gases (Group Zero)

Objectives

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

Introduction to Noble Gases

• Group Zero is known as the noble gases.
• Noble gases were not included in Dmitri Mendeleev's original periodic table as they were discovered later.
• Key characteristic: Noble gases are very unreactive elements.

Structure of Noble Gases

Helium

• Helium is the first noble gas.
• Helium atoms have 2 electrons, both in the first energy level.
• The first energy level can hold a maximum of 2 electrons, making helium stable and unreactive.

Neon

• Neon is another noble gas.
• Neon atoms have 10 electrons: 2 in the first energy level, 8 in the second energy level.
• The second energy level can hold a maximum of 8 electrons, making neon stable and unreactive.

Argon

• Argon is also a noble gas.
• Argon atoms have 8 electrons in its outer energy level, making it stable and unreactive.

Key Fact

• All noble gases have a full outer energy level, making them unreactive.

Boiling Points of Noble Gases

• All noble gases have boiling points lower than room temperature, explaining why they are gases at room temperature.
• Boiling points increase with increasing relative atomic mass.
  • Helium has the lowest relative atomic mass (4) and the lowest boiling point.
  • Radon has the highest relative atomic mass (222) and the highest boiling point.

Additional Resources

• Practice questions on this topic are available in the revision workbook.