1. Zero group
or group 18 is a family of inert gases also called as noble gases or rare
gases.
2.
In their atoms, all the electronic shells including the outermost shell are
completely filled. They have stable electronic configuration with complete
duplet (Helium) or complete octet (Neon, Argon etc).
3.
So, atoms do not gain, lose or share electrons and hence have zero valency.
4. Hence, the
family of noble gases is called as zero group.