Question

how do I find the valance electrons? no further info

Answer 1

You could use the periodic table's columns.
Generally, group 1 has 1 valence electron
Group 2 has 2 valence electrons
Group 13-18 has 3-8 valence electrons

But the best way might be using electron configurations to just count them.

Answer 2

You start by locating the valence electrons on a periodic table, while using the group number. For groups 1-2, the number of valence electrons is equivalent to the group number. The final digit of the group number corresponds to 13-18.