Question

identify the correct lewis structure for so₃²⁻. select the single best answer.

Explanation:

Step1: Count valence electrons

S has 6 valence - electrons, each O has 6 valence - electrons, and the ion has a 2 - charge. So total valence electrons = 6+3×6 + 2=26.

Step2: Determine central atom

S is the central atom as it is less electronegative than O.

Step3: Connect atoms and distribute electrons

Connect S to each O with a single bond first, using 6 electrons. Then distribute the remaining 20 electrons as lone - pairs on O atoms to satisfy the octet rule. But to minimize formal charges, we can form a double - bond between S and one of the O atoms.
The correct Lewis structure has S as the central atom, single - bonded to two O atoms with a negative charge on each of those O atoms and double - bonded to one O atom.

Answer:

The third option (where S is single - bonded to two O atoms with a negative charge on each of those O atoms and double - bonded to one O atom) is the correct Lewis structure for $\text{SO}_{3}^{2 - }$.