Question

Element A, with three electrons in its outer energy level, is in Period 4 of the periodic table. How
does the number of its valence electrons compare with that of Element B, which is in Group 13
(IIIA) and Period 6? Use Lewis structures to help you express your answer.

Answer 1

Element A: Ga

Element B: Tl

The same number of valence electrons, the electronic formula of the last level:

$$ns^2np^1$$