The oxygen atom is smaller than the sulfur atom because ) the outer electrons of oxygen are more effectively screened from the nuclear charge than are sulfur’s outer electrons. (2) the outer orbitals of oxygen are located closer to the nucleus than those of sulfur. (3) the oxygen atom is larger than the sulfur atom. (4) the outer electrons of oxygen are less effectively screened from the nuclear charge than are sulfur’s outer electrons. (5) the outer orbitals of oxygen are located farther away from the nucleus than those of sulfur.

Option (2) is the correct answer.

Explanation:

Atomic number of oxygen atom is 8 and its electronic distribution is 2, 6. So, it contains only 2 orbitals which are closer to the nucleus of the atom.

As a result, the valence electrons are pulled closer by the nucleus of oxygen atom due to which there occurs a decrease in atomic size of the atom.

Whereas atomic number of sulfur is 16 and its electronic distribution is 2, 8, 6. As there are more number of orbitals present in a sulfur atom so, the valence electrons are away from the nucleus of the atom.

Hence, there is less force of attraction between nucleus of sulfur atom and its valence electrons due to which size of sulfur atom is larger than the size of oxygen atom.

Thus, we can conclude that the oxygen atom is smaller than the sulfur atom because the outer orbitals of oxygen are located closer to the nucleus than those of sulfur.