5.

What characteristic distinguishes helium (He) from the other noble gases?

Helium has a strong odor.

Helium is highly reactive.

Helium has two valence electrons.

Helium has a milky-white color.

None of the above.

The characteristic that distinguishes helium from the other noble gases is that helium has the lowest atomic number and the lowest density of all the noble gases.

The characteristic that distinguishes helium (He) from the other noble gases is that helium has two valence electrons.