Question

The atomic size increases from right to left and from top to bottom on the periodic table of elements. As a result, some of the elements in period one are:
Select one:
a. larger than the elements in period two.
b. more reactive that the elements in period two.
c. less stable than the elements in period two.
d. are exactly the same weight as the elements in period two.

Answer 1

i thought it was B, but i was incorrect.

Answer 2

@Hoslos @Love_Ranaa

Answer 3

It cannot be B, because as we go down the group, the number of electrons and so the weight icreases, as well as the shielding effect or the number of shells. Hence, the feeling of attraction withthe nucleus of the other atom to promote reaction is less. Hence they do not become more reactive.
The answer is C, because neither of the elements in period 1 respected the octect rule, stating that an atom is fully stable when its outermost orbital has 8 electrons. Hydrogen has 0 and Helium has 2.