Compared with Group 6A elements, Group 2A elements have

a. more atoms in the ground state.

b. more valence electrons.

c. more isotopes.

d. fewer valence electrons.

The periodic table of elements is divided into eight groups, excluding the transition metals. The elements in these groups are placed in their respective positions due to the number of valence electrons they have. The valence electrons of an atom are the electrons in the outermost shell of the atom. Thus, the atoms of the elements in group 1 have 1 valence electron, those in group 2 have 2 valence electrons and so on. So an element in group 6 will have 6 valence electrons, which is more than that of an element from group 2. Therefore, the answer is D. fewer valence electrons.