Noble Gases: The Inert Crowd

Why it matters

Imagine a gas so uninterested in chemistry that it refuses to hold hands with anything, even when forced into a crowded room. Even a flame plunged into a jar of argon simply goes out — there is nothing for it to react with.

Predict first

Why do noble gases like Neon and Argon rarely form compounds?

A full outer shell is the goal — an octet for most noble gases, but a duplet (2 electrons) for helium. Noble gases already have a full outer shell, so they have no drive to gain, lose, or share electrons.

• They are too heavy to move fast enough to react.
• They have a full outer shell of electrons, making them stable. — correct
• They are found in nature as diatomic molecules.
• They repel all other atoms with strong negative charges.

What you do

Build a neon atom — 10 protons, 10 neutrons and 10 electrons (mass number 20). Arrange the electrons in shells and notice the outer shell is full.

Check yourself

What is the valency of a noble gas?

Valency is the combining capacity. Since noble gases are stable and don't combine, their valency is 0.

Which configuration represents a stable noble gas atom?

2, 8 represents Neon. The outer shell has 8 electrons (octet), which is the stable configuration.

• 1
• 0 — correct
• 8
• 2, 1
• 2, 8 — correct
• 2, 7
• 2, 8, 1