Question

Which family of elements tends to exist as monatomic gases?

Answer 1

I think inert gases ....as they do not form any type of bonds...

hope it helps you

Answer 2

The noble gases or inert gases , group 18 of modern periodic table tends to exist as Mono atomic gases.

Reason:
All the inert gases like
⇒Helium,
⇒Neon
⇒Argon
⇒Krypton
⇒Xenon
⇒Radon
are highly nonreactive because they have octet configuration in their valence shell except for He.
The valency of Inert gases is zero. Hence they exist as mono atomic gases