Question

Draw the best Lewis structure for Cl₃⁻. What is the formal charge on the central Cl atom?

1) -1
2) 0
3) 1
4) 2
5) -2

Answer 1

The best Lewis structure for Cl₃− has the central Cl atom with a formal charge of 0. The formal charge is calculated by subtracting the number of bonds and non-bonding electrons from the number of valence electrons in the free atom.

Step-by-step explanation:

The question asks about the best Lewis structure for the molecule Cl₃− and the formal charge on the central Cl atom. To draw the Lewis structure and calculate the formal charge, we follow these steps:

• Since Cl has 7 valence electrons, for the molecule Cl₃−, which contains three Cl atoms and an extra electron due to the negative charge, there's a total of 7*3+1 = 22 valence electrons.
• Place a Cl atom in the center and bond it to two other Cl atoms. Distribute the remaining electrons to fulfill the octet rule, remembering to include the additional electron for the overall charge.
• Once all electrons are placed, calculate the formal charge for each Cl atom: Formal charge = (Number of valence electrons in the free atom) - (Number of bonds) - (Number of non-bonding electrons). In this case, the central Cl will have a formal charge of 0 as it shares its electrons with the other two Cl atoms equitably.

Thus, the best Lewis structure for Cl₃− will have the central Cl atom with a formal charge of 0, making option 2 the correct answer.