Which of the following structures is the most preferred and hence of lowest energy for SO ₃ ?

Step-by-step solution

Formal charges help in the selection of the lowest energy structure from a number of possible Lewis structures for a given species. Generally the lowest energy structure is the one with the smallest formal charges on the atoms. Formal charge on an atom : = total no. of valence electrons-non-bonding electrons - 1 2 bonding electrons. For Lewis structure of SO ₃ Formal charge on S atom =6-0- 1 2 12=0 Formal charge on three O atoms =6-4- 1 2 4=0