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. it increases then decreases i.e +1, +2, +3, +4, +5, -2, -1 then 0.
2. group 6 elements have more valence electrons than group 2.
3.fluorine is the most reactive because reactivity and electronegativity reduces down the group.