Question

What do elements of the same period have in common?

number of valence electrons
O number of shells
O number of protons
O atomic mass

Answer 1

its actually the number of shells

Step-by-step explanation:

valence electrons are the same down any group. atomic orbitals, or shells, are the same across periods

Answer 2

no of valence electrons

Step-by-step explanation:

because valence electrons are the electrons present in the outer orbital