IGCSE · Practice questions · Noble gases

Full shells, useful gases.

Six original Cambridge-style questions on the noble gases: electronic structure, unreactivity, trends and uses.

Original questions All questions on this page are original work, written in the Cambridge IGCSE style. They are not from past papers. They test the same concepts and skills the syllabus rewards.

Keep these straight

Full outer shell, no reaction.

Monatomic and unreactive.
Full outer shells: He 2, Ne 2,8, Ar 2,8,8.
Down the group: boiling point and density increase.
Uses depend on unreactivity plus one other property.

Explain

[2 marks]

Explain, in terms of electrons, why the noble gases are unreactive.

Their atoms have full outer electron shells. ✓
So they do not need to lose, gain or share electrons to become stable. ✓

Recall

[3 marks]

Give the electronic configurations of helium, neon and argon.

Helium: 2. ✓
Neon: 2,8. ✓
Argon: 2,8,8. ✓

Recall

[2 marks]

State one use of helium and explain it in terms of its properties.

Filling balloons or airships. ✓
It is much less dense than air and unreactive, so it does not burn. ✓

Explain

[2 marks]

Suggest why argon, rather than air, is used inside filament light bulbs.

The filament is very hot and would react with the oxygen in air (burn out). ✓
Argon is unreactive, so the filament lasts much longer. ✓

Analysis

[2 marks]

Name the noble gas that has the same electronic configuration as (a) a calcium ion, Ca²⁺, and (b) an oxide ion, O²⁻.

(a) argon (Ca²⁺ is 2,8,8). ✓
(b) neon (O²⁻ is 2,8). ✓

Recall

[1 marks]

Explain the meaning of the term monatomic.

Existing as single, separate atoms rather than as molecules. ✓

Mark this once you have attempted all six and checked your working. It records a Practiced badge on the topic and adds a one-time bonus. Revealing the solutions alone does not count.