Noble gases

Noble gases, including helium, argon, neon, and xenon, are colorless and odorless. They are largely unreactive due to their full outer electron shells. Previously thought to form no compounds, some like xenon tetrafluoride have been discovered.

Which of the following elements is not a noble gas?

• Oxygen

• Neon

• Argon

• Helium

What is a common characteristic of noble gases?

• They have incomplete electron shells.

• They are highly reactive.

• They are colorless and odorless.

• They are metals.

Why are noble gases generally unreactive?

• They are too heavy to react.

• They have a full outer shell of electrons.

• They are not found in nature.

• They are solid at room temperature.

Which noble gas compound was discovered, challenging the belief that noble gases form no compounds?

• Xenon tetrafluoride

• Neon bromide

• Argon chloride

• Helium oxide

Historically, what was believed about the reactivity of noble gases?

• They were highly reactive.

• They were only reactive with metals.

• They could form many compounds.

• They formed no compounds.