What happens to the distance between neon atoms as they heat up? A) They get closer together. B) They get farther apart. C) They disappear.

What the question is really asking

Heating a substance adds thermal energy. For a gas like neon, that extra energy mostly shows up as faster-moving atoms, which affects how much space the gas takes up.

Neon is a noble gas with weak attractions

Neon atoms in a gas are not bonded to each other. The only attractions are very weak intermolecular forces, so there is nothing holding the atoms at a fixed spacing.

Why heating increases spacing in a gas

When temperature increases, the average kinetic energy increases:

$$\text{average kinetic energy} \propto T$$

Faster atoms hit the container walls more often and with more force. If the container can expand (like a balloon), the volume increases. With more volume available, the same number of atoms are spread out more, so the average distance between neon atoms increases.

Eliminating the other choices

• A) Closer together would be expected when cooling or compressing a gas, not heating it.
• C) Disappear is not physical; atoms do not vanish when heated under normal conditions.