Draw the Lewis structure for the polyatomic hydroperoxyl (HO2) anion. Be sure to indude all esonance structures that satisty the octet rule
The Correct Answer and Explanation is :
The hydroperoxyl (HO₂⁻) anion consists of a hydrogen atom (H) bonded to a peroxide group (O₂⁻). This molecule contains two oxygen atoms with a negative charge and a single hydrogen atom attached to one oxygen atom. Let’s walk through the steps to draw the Lewis structure and identify the resonance structures.
Step 1: Count the Valence Electrons
- Hydrogen (H) contributes 1 valence electron.
- Each oxygen (O) atom contributes 6 valence electrons.
- The negative charge on the anion adds an extra electron.
Thus, the total number of valence electrons is: 1 (H) + 2 × 6 (O) + 1 (negative charge) = 13 valence electrons.
Step 2: Connect the Atoms
Hydrogen is typically bonded to an oxygen atom in this structure. The two oxygen atoms are bonded to each other, forming a peroxide bond (O–O).
Step 3: Draw the Bonding
Start by drawing the H–O–O bond. This consumes 2 electrons (one bond between H and O, one between the two O atoms).
Step 4: Complete the Octet of Oxygen Atoms
Each oxygen should have a full octet (8 electrons). The O atoms are bonded, so they each need more electrons. Add lone pairs of electrons to each oxygen atom to complete their octets. Oxygen atoms typically have 2 lone pairs when bonded to another atom and the hydrogen.
Step 5: Account for the Negative Charge
To account for the negative charge on the molecule, place the extra electron on one of the oxygen atoms. This means that one of the oxygen atoms will carry the negative charge, and the other will have a neutral charge.
Step 6: Identify the Resonance Structures
Since oxygen-oxygen bonds can have some flexibility in bonding, there are two possible resonance structures. In one structure, the negative charge resides on the second oxygen, while in the other, it resides on the first oxygen.
Lewis Structure:
H H
| |
O⁻─O O
In both resonance structures:
- Each oxygen atom has a full octet.
- The negative charge is on one oxygen in each resonance form.
Conclusion:
The hydroperoxyl anion (HO₂⁻) exhibits resonance, where the negative charge is delocalized between the two oxygen atoms. Each resonance structure follows the octet rule, ensuring that both oxygen atoms have full electron configurations.