Question

What happens to number of valence electrons in atoms of elements as we go down a group of the periodic table ?

Answer 1

It should be noted that, during the classification of elements,all the elements with similar valance electrons are placed in same group in a periodic table.

Hence, when we move down the group, the valence shell changes, because the period number changes, but the valency remains the same.

For example, All the element the group I has 1 valence electron, it has +1 valency.

in group 1; -. Li(Lithium)- valence shell is 2s1 while the second element Na(sodium) has valence shell 3s1

But, in all the elements the valency remains the same as 1 because they have only one electron in their outermost s-orbital.