Which of the following is an electron-deficient compound?

Options

A. `BeCI_(2)`
B. `BCI_(3)`
C. `C CI_(3)`
D. `PCI_(3)`

Answer

To determine which of the given compounds is an electron-deficient compound, we need to analyze the electron configuration and bonding of each compound. Let's evaluate the options step by step.

### Step 1: Analyze BeCl2
- **Beryllium (Be)** has an atomic number of 4, with an electronic configuration of 1s² 2s². It has 2 electrons in its outermost shell and typically forms 2 bonds.
- In BeCl2, beryllium forms 2 bonds with 2 chlorine atoms. However, beryllium does not complete its octet since it only has 4 electrons (2 from itself and 2 from chlorine).
- **Conclusion**: BeCl2 is not electron-deficient since it is stable with 4 electrons.

### Step 2: Analyze BCl3
- **Boron (B)** has an atomic number of 5, with an electronic configuration of 1s² 2s² 2p¹. It has 3 electrons in its outermost shell and typically forms 3 bonds.
- In BCl3, boron forms 3 bonds with 3 chlorine atoms. Boron ends up with only 6 electrons in its outermost shell (3 from itself and 3 from chlorine).
- **Conclusion**: BCl3 is electron-deficient because boron does not complete its octet.

### Step 3: Analyze CCl4
- **Carbon (C)** has an atomic number of 6, with an electronic configuration of 1s² 2s² 2p². It has 4 electrons in its outermost shell and typically forms 4 bonds.
- In CCl4, carbon forms 4 bonds with 4 chlorine atoms, completing its octet with 8 electrons (4 from itself and 4 from chlorine).
- **Conclusion**: CCl4 is not electron-deficient as it completes its octet.

### Step 4: Analyze PCl3
- **Phosphorus (P)** has an atomic number of 15, with an electronic configuration of 1s² 2s² 2p⁶ 3s² 3p³. It has 5 electrons in its outermost shell and typically forms 3 bonds.
- In PCl3, phosphorus forms 3 bonds with 3 chlorine atoms, completing its octet with 8 electrons (5 from itself and 3 from chlorine).
- **Conclusion**: PCl3 is not electron-deficient as it completes its octet.

### Final Conclusion
The only compound among the options that is electron-deficient is **BCl3**.

### Summary of Steps
1. Analyze the electronic configuration and bonding of BeCl2.
2. Analyze the electronic configuration and bonding of BCl3.
3. Analyze the electronic configuration and bonding of CCl4.
4. Analyze the electronic configuration and bonding of PCl3.
5. Conclude that BCl3 is the electron-deficient compound.