Group 0 — Noble Gases | Chemistry

📖 In-Depth Theory

Properties of the Noble Gases

GROUP 0 (also called Group 18) contains the NOBLE GASES:

Helium (He) — atomic number 2.

Neon (Ne) — atomic number 10.

Argon (Ar) — atomic number 18.

Krypton (Kr) — atomic number 36.

Xenon (Xe) — atomic number 54.

Radon (Rn) — atomic number 86.

All noble gases are:

COLOURLESS gases at room temperature.

MONATOMIC — they exist as single atoms, not molecules (unlike O₂, N₂, Cl₂).

EXTREMELY UNREACTIVE — they do not form compounds under normal conditions.

DENSER than air as you go down the group.

Have very LOW BOILING POINTS — they remain gases until very cold.

Why Noble Gases Are Unreactive

Noble gases are unreactive because they have FULL OUTER ELECTRON SHELLS:

Helium: 2 electrons (full 1st shell).

Neon: 2.8 (full 1st and 2nd shells).

Argon: 2.8.8 (full 1st, 2nd and 3rd shells).

A full outer shell is the most STABLE electron configuration — the atom has no tendency to gain, lose or share electrons.

This is why other elements react — they are trying to ACHIEVE the stable full outer shell configuration of a noble gas:

Group 1 metals lose 1 electron → achieve noble gas configuration.

Group 7 non-metals gain 1 electron → achieve noble gas configuration.

Non-metals share electrons (covalent bonds) to achieve full outer shells.

Trends Down Group 0

Going DOWN Group 0 (from He to Rn):

ATOMIC RADIUS increases — more electron shells are added.

BOILING POINT INCREASES:

He: −269°C, Ne: −246°C, Ar: −186°C, Kr: −153°C, Xe: −108°C.

Larger atoms have stronger LONDON DISPERSION FORCES between them (a type of intermolecular force caused by temporary dipoles in electron clouds).

More electrons → greater temporary dipoles → stronger forces → higher boiling point.

DENSITY increases down the group.

The reactivity stays VERY LOW throughout — all noble gases are essentially inert under normal conditions.

⚠️ Common Mistake

Noble gases are MONATOMIC — they exist as single atoms (He, Ne, Ar) — NOT as molecules (not He₂ or Ne₂). This is because they are already stable with full outer shells and have no reason to form bonds. Other non-metals like oxygen (O₂) and nitrogen (N₂) exist as diatomic molecules because they share electrons to achieve full outer shells.

📌 Key Note

Noble gases: Group 0, full outer shells, extremely unreactive, monatomic. Boiling point increases down group (bigger atoms, stronger London dispersion forces). Helium: 2 outer electrons (full 1st shell). All others: 8 outer electrons (full outer shell).

🎯 Matching Activity — Match the Noble Gas Property

Match each property to noble gases and explain why. — drag the symbols on the right to match the component names on the left.

Very unreactive

Drop here

Monatomic

Drop here

Boiling point increases down group

Drop here

Colourless gases

Drop here

Helium — lighter than air

Drop here

Exist as single atoms — already stable, no need to bond with other atoms

Larger atoms have stronger London dispersion forces — more electrons, larger temporary dipoles

All noble gases are transparent and gaseous at room temperature

Helium has only 2 electrons and 2 protons — very low density, used in balloons

Full outer electron shells — no tendency to gain, lose or share electrons

🎯 Test Yourself

Question 1 of 2

1. Why are noble gases so unreactive?

2. Argon has a higher boiling point than neon. Why?

⭐ How Well Do You Understand This Topic?

Be honest with yourself — this helps you know what to revise!

Don't get it Getting there Nailed it!

🤖 Ask Mr Badmus AI

Stuck? Just ask! 💬

I'll use FIFA for calculations and flag Higher/Triple content clearly.

🧪 Group 0 — Noble Gases

Properties of the Noble Gases

Why Noble Gases Are Unreactive

Trends Down Group 0

Mr. Badmus AI