Which of these pairs of elements have the same number of valence electrons?
A) oxygen (O) and bromine (Br)
B) selenium (Se) and bromine (Br)
C) carbon (C) and lead (Pb)
D) oxygen (O) and carbon (C)
E) sodium (Na) and magnesium (Mg)
Both carbon and lead belong to Group IV elements, and thus they have the same number of valence electrons. In each of the other options, the two elements belong to different groups, and thus they do NOT have the same number of valence electrons.
