Group 8/0 – The Noble Gases
Group 8/0 of the periodic table contains the noble gases – a group of unreactive non-metals found on the far right of the periodic table. They are monoatomic gases and have full outer electron shells, which makes them very stable.
Elements in Group 8/0
Element | Symbol | Atomic Number |
Helium | He | 2 |
Neon | Ne | 10 |
Argon | Ar | 18 |
Krypton | Kr | 36 |
Xenon | Xe | 54 |
Radon | Rn | 86 |
These elements exist as single atoms (monoatomic) and are found in small amounts in the air.
Electron structure and stability
All noble gases have full outer shells of electrons:
- Helium has 2 electrons (full first shell)
- The rest have 8 electrons in their outer shell (a full second shell and beyond)
💡 A full outer shell means the atoms are very stable and do not need to gain or lose electrons, so they are unreactive.
Physical properties
Property | Trend down Group 8/0 |
Boiling point | Increases |
Density | Increases |
Reactivity | Remains very low |
State at room temp | All are gases |
These trends are due to increasing atomic mass and stronger intermolecular forces down the group.
Uses of noble gases
Because they are unreactive, noble gases have practical uses:
- Helium – balloons and airships (lighter than air, non-flammable)
- Neon – advertising signs (glows red-orange)
- Argon – used in light bulbs (stops filament reacting with oxygen)
- Krypton/Xenon – used in specialist lighting (e.g. flash photography)
Questions
- What makes noble gases unreactive?
- What does monoatomic mean?
- What trend is seen in boiling points down Group 8/0?
- Which noble gas is used in balloons?
- How many outer shell electrons does neon have?
Summary
- Noble gases have full outer shells, making them stable and unreactive.
- They are monoatomic and exist as gases at room temperature.
- Boiling points and densities increase down the group.
- Used in lighting, balloons, and unreactive environments.
- Their stability is due to their complete electron shells.