Question

is the number of Valence Electrons l i v e p c n o f are same for all these elements

Answer 1

For main group elements, the number of valence electrons is the same in every element in the same group.

[Example]
Group 1 elements have 1 valence electron in the s orbital.
H 1s1
Li [He]2s1
Na [Ne]3s1
etc…

Group 16 elements have 6 valence electrons in sand p orbitals.
O [He]2s22p4
S [Ne]3s23p4
Se [Ar]3d104s24p4
…

However, some transition metals don't follow this rule.
For example, let's see the electronic structure of Group 8.
Fe [Ar]3d64s2
Ru [Kr]4d75s1
Os [Xe]4f145d66s2