Draw the Lewis structure of the hypochlorite ion, ClO−, which is used to clean swimming pools as its calcium salt.

The Correct Answer and Explanation is:

Lewis Structure of Hypochlorite Ion (ClO⁻)

The correct Lewis structure for the hypochlorite ion, ClO⁻, is:

:Cl–O:⁻

Or more clearly represented with lone pairs:

  ..
:Cl:–O:⁻
  ..

Step-by-Step Explanation (Approx. 300 Words)

The hypochlorite ion (ClO⁻) consists of one chlorine (Cl) atom and one oxygen (O) atom, with an overall charge of -1. Drawing the Lewis structure requires considering the valence electrons and ensuring that the octet rule is satisfied for both atoms, where applicable.

1. Count Total Valence Electrons

Chlorine (Cl) has 7 valence electrons (Group 17).
Oxygen (O) also has 6 valence electrons (Group 16).
The negative charge (⁻1) adds one extra electron.

Total = 7 (Cl) + 6 (O) + 1 (extra electron) = 14 valence electrons

2. Determine the Skeleton Structure

Place Cl and O next to each other: Cl—O

We’ll start with a single bond between Cl and O.

3. Distribute Remaining Electrons

A single bond uses 2 electrons, leaving 12 electrons.
Distribute these as lone pairs to complete octets:
- Give O three lone pairs (6 electrons).
- Give Cl three lone pairs (6 electrons).

Now each atom has 8 electrons (2 from the bond + 6 from lone pairs).

4. Check Formal Charges

Formal charge = (Valence e⁻) – (Non-bonding e⁻) – (Bonding e⁻ / 2)

Oxygen: 6 – 6 – 1 = -1
Chlorine: 7 – 6 – 1 = 0

The total formal charge is –1, matching the ion’s actual charge. This confirms the structure is valid.

5. Octet Rule and Stability

Oxygen follows the octet rule.
Chlorine can expand its octet but does not need to here.
The structure is stable and reflects the actual electron distribution in hypochlorite.

This structure explains why hypochlorite is a good oxidizing agent: the negatively charged oxygen can donate an electron pair or participate in redox reactions, which is useful in disinfection applications like pool cleaning.