Number of sigma and pi bonds in `ClO_(2)^(-)` ion

Options

A. `2 sigma and 2pi`
B. `2 sigma and 1pi`
C. `1 sigma and 2pi`
D. `3 sigma and 2pi`

Answer

To determine the number of sigma (σ) and pi (π) bonds in the ClO₂⁻ ion, we can follow these steps:

### Step 1: Identify the central atom and its valence electrons
- The central atom in the ClO₂⁻ ion is chlorine (Cl).
- Chlorine has an atomic number of 17, which gives it the electronic configuration of 2, 8, 7. Therefore, chlorine has 7 valence electrons.

**Hint:** Remember that the central atom is usually the least electronegative element in the molecule.

### Step 2: Determine the bonding structure
- In ClO₂⁻, chlorine forms a double bond with one oxygen atom and a single bond with the other oxygen atom.
- The double bond uses 2 electrons, and the single bond uses 1 electron.

**Hint:** Count the number of bonds formed with surrounding atoms to understand how many valence electrons are used.

### Step 3: Calculate the remaining valence electrons
- After forming the double bond (2 electrons) and the single bond (1 electron), a total of 3 electrons are used.
- Since chlorine started with 7 valence electrons, there are 4 electrons left.
- These 4 electrons can be arranged as 2 lone pairs on the chlorine atom.

**Hint:** After forming bonds, check how many electrons are left to determine lone pairs.

### Step 4: Identify the types of bonds
- In the ClO₂⁻ ion:
- The double bond between Cl and one O consists of 1 sigma bond and 1 pi bond.
- The single bond between Cl and the other O consists of 1 sigma bond.

**Hint:** Remember that every single bond is a sigma bond, and a double bond consists of one sigma and one pi bond.

### Step 5: Count the total number of sigma and pi bonds
- Total sigma bonds:
- 1 sigma bond from the Cl=O double bond
- 1 sigma bond from the Cl-O single bond
- Total = 1 + 1 = 2 sigma bonds

- Total pi bonds:
- 1 pi bond from the Cl=O double bond
- Total = 1 pi bond

**Hint:** Add up the contributions from each bond type to get the final counts.

### Final Answer
- The ClO₂⁻ ion has **2 sigma bonds** and **1 pi bond**.