Which of the following is the correct Lewis structure of O₃? 

The correct answer is d.

Key Points

• Each of the three oxygen atoms in an O₃ molecule has six valence electrons. This totals 18 valence electrons for the molecule.
• In the central oxygen atom, two bonds are formed: one with each of the two other Oxygen atoms.
• It utilizes 4 out of 18 electrons, leaving us with 14 electrons.
• The rest of the 14 electrons are distributed as lone pairs. Each oxygen atom receives three lone pairs (2 electrons form a pair), which account for 6 x 3 = 18 electrons. This includes the electrons shared in the bonds.
• But for total 18 electrons, two electrons are needed from somewhere else.
• These electron pair is provided by another oxygen atom, forming a double bond between the central oxygen and one of the peripheral oxygen atoms.

So, the Lewis structure of O3 can be denoted as O-O=O, where "-" denotes a single bond containing 2 electrons and "=" denotes a double bond which contains 4 electrons. One oxygen forms a single bond with the central oxygen, while another forms a double bond. Each oxygen atom also has 6 electrons (or 3 pairs) forming lone pairs around them.