Question

1.As you move from left to right across a period,the number of valence electrons
-increases
-stays the same
-increases and then decreases
-decreases
2.Compared with group 2A elements, group 64 elements have
-more atoms in the ground state
-more valence electrons
-more isotopes
-fewer valance electrons
3.which of the following group 7A elements is the most reactive?
-CI(chlorine
-I(iodine)
-F(fluorine)
-Br(bromine)

Answer 1

1. Increases. It's moving across the periodic table like that. Helium (He) has more valance electrons than Hydrogen (H), for example.
2 I assume you mean group 6A? In that case, more valance electrons. Beryllium (Be) has two valence electrons, Oxygen (O) has 6.T
3 Fluorine (F). Reactivity decreases as one moves down the periodic table.