Noble Gases Have Many Uses

What students typically write

“Noble gases are useless because they don’t react with anything.” Or: “Since noble gases are inert, they have no practical applications.”

Students learn that noble gases are unreactive and jump to the conclusion that unreactive means useless. In fact, the opposite is true: their unreactivity is their most valuable property.

Why it is wrong

Many applications require a gas that will not react. In those situations, a reactive gas would be dangerous or would interfere with the process. Noble gases fill that role perfectly.

Helium is used in balloons and airships because it is less dense than air (so it provides lift) and is non-flammable (unlike hydrogen, which caused the Hindenburg disaster). Its unreactivity makes it safe.

Neon is used in illuminated advertising signs. When electricity passes through neon gas at low pressure, it emits a characteristic red-orange glow. Other noble gases produce different colours and are used similarly.

Argon is used to fill incandescent light bulbs. The tungsten filament would burn in air (react with oxygen) but survives in argon because argon does not react with it. Argon is also used as a shielding gas in welding, where it prevents the hot metal from reacting with oxygen and nitrogen in the air.

In every case, the use depends on the noble gas NOT reacting. Unreactive does not mean useless; it means safely usable where reactive gases would cause problems.

What the mark scheme actually wants

A typical question: “State one use of argon and explain why it is suitable for this use.” [2]

Marking points:

1. Use: filling light bulbs / welding (1 mark)
2. Explanation: argon is unreactive/inert, so it does not react with the hot filament/metal (1 mark)

Both marks require linking the use to the property. Just naming a use without explaining why the inertness matters may not earn full marks.

Worked example: wrong vs right

Question: Explain why helium is used in airships rather than hydrogen. [2]

Wrong answer: “Helium is a noble gas so it has no use in reactions, but they put it in airships anyway because it is light.” This scores 1/2 at most. The density point is there, but the safety advantage is missed and the dismissive tone about “no use” shows the misconception.

Right answer: “Helium has a low density, so it provides lift (1). Helium is non-flammable / unreactive, so it is safer than hydrogen, which is flammable (1).” This scores 2/2.

How to avoid this mistake

Whenever you describe a noble gas as “unreactive”, immediately follow it with “which makes it suitable for…” and name the application. Train the connection: inertness is a feature, not a limitation.

For the full coverage of noble gas properties and uses, see noble gases. Periodic table trends and electron configurations are covered at arrangement and trends.