Group 0Edexcel GCSE Chemistry: Revision notes
Section 1
Where are the noble gases and why are they inert?
The noble gases are the elements in Group 0 (the far right column) of the periodic table: helium, neon, argon, krypton, xenon and radon.
They are described as chemically inert (unreactive) because their atoms have a full outer shell of electrons. A full outer shell is a very stable electronic configuration, so noble gas atoms have no tendency to gain, lose or share electrons to form bonds with other atoms.
Always explain inertness in terms of electronic configuration — 'full outer shell of electrons' — rather than just stating 'they don't react'.
Section 2
What pattern do the physical properties of the noble gases show?
Moving down Group 0 (helium → neon → argon → krypton → xenon):
- Boiling point increases
- Density increases
This pattern lets you predict the physical properties of noble gases you haven't been told about directly — for example, radon (below xenon) should have an even higher boiling point and density than xenon.
If given boiling point data for helium, neon and argon and asked to predict krypton's, extrapolate the increasing trend down the group.
Section 3
How do the uses of noble gases relate to their properties?
Noble gas uses depend directly on being inert, having low density, and/or being non-flammable:
| Use | Property exploited |
|---|---|
| Filling light bulbs (argon) | Inert — stops the hot filament reacting with oxygen and burning out |
| Filling party/weather balloons and airships (helium) | Low density (lighter than air) and non-flammable (unlike hydrogen) |
| Providing an inert atmosphere for welding | Inert — stops the hot metal reacting with oxygen in the air |
Helium is used in balloons instead of hydrogen mainly because it is non-flammable, not just because it is light — hydrogen is even lighter but is a fire risk.
Must Know
- Noble gases are in Group 0; they are chemically inert because their atoms have a full outer shell of electrons
- Going down Group 0, boiling point and density both increase
- Argon is used in light bulb filaments and welding atmospheres because it is inert
- Helium is used in balloons/airships because it has low density and is non-flammable
- Use the trend down the group to predict properties of noble gases not directly given data
That's the notes covered.
Carry on to the next subtopic.