## Chemistry: Molecular Approach (4th Edition)

a. In the $3rd$ period , $[Ne]3s^{2}3p^{1}$ configurations will have 3 valence electrons. This is the configuration of aluminium b. In the $3rd$ period , $[Ne]3s^{2}3p^{4}$ configuration is of sulfur c. In the $3rd$ period , $[Ne]3s^{2}3p^{6}$ configuration is of argon d. In the $3rd$ period , $[Ne]3s^{2}$ configuration is of magnesium.