which is true of elements on a periodic table in the same group (family)?
a; elements in the same family have similar chemical properties because they have the same number of electron shells.
b; elements in the same family have similar chemical properties because they have the same number of valence electrons.
c; elements in the same family have few similar properties as they have different numbers of electron shells.
d; elements in the same family are always the same type of elements and have the same number of protons.