Answer:
periods 3-5
Explanation:
If you know your periodic table well, this is simple. but to explain it, periods 3-5 have elements that have electrons that fill the s, p and d orbitals. if you do not know, the s orbital starts off with the first period and the second period until you get totto the right side which is where the o block starts. the block is all of the transition metals and they all fill the s and p or ital as well.
