Set of elements having one electron in their valence shell is `:-`

Which element is having 5 electrons in valence shell?

What is the general name of the elements having 8 electrons in the valence shell of their atoms ?

What is the general name of the elements having 8 electrons in the valence shell of their atoms ?

An element has 8 electrons in the valence shell

Name any two elements that have two electrons in their valence shell.

An atom of an element has one electron in the valence shell and the two inner shells have 8 electrons each. Find the atomic number of that element.