Answer
a) 1 valence electron (Li, Na, K, Rb, Cs)
b) 6 valence electrons (Se)
c) 4 valence electrons (C, Si, Ge, Sn, Pb)
d) 8 valence electrons (Group 8A)
Work Step by Step
Valence electrons are equal to the group number the element belongs to for groups 1A-8A, with the exception of Helium, because it only contains 2 electrons total. This does not apply to B Group Transition elements.
a) Li, Na, K, Rb, Cs are in Group 1A, so they have 1 valence electron each.
b) Se is in Group 6A, so it has 6 valence electrons.
c) C, Si, Ge, Sn, and Pb are in Group 4A, so they have 4 valence electrons each.
d) The elements in Group 8A have 8 valence electrons each (except He).
