According to the configuration of Ar (1s2 2s2 2p6 3s2 3p6), it has 18 electrons. Furthermore, sulphur has the next configuration 1s2 2s2 2p6 3s2 3p4. In order to achieve the Octect in its structure, S which has an atomic number equal to 16, has to accept 2 electrons to fill its outermost shell thereby becoming negatively charged, S-2
Answer: Sulphur, S
