According to Lewis and Kossel approach, which of the following molecule has complete octet of the central atom?

Options

A. LICI
B. `BeH_2`
C. `BCI_3`
D. `CO_2`

Answer

To determine which molecule has a complete octet for the central atom according to the Lewis and Kossel approach, we will analyze each option step by step.

### Step 1: Analyze LiCl
- **Valence Electrons**: Lithium (Li) has 1 valence electron, and Chlorine (Cl) has 7 valence electrons.
- **Bond Formation**: When Li and Cl bond, Li donates its 1 electron to Cl.
- **Electron Count**: Li now has no electrons, and Cl has 8 electrons (7 original + 1 from Li).
- **Octet Status**: Li does not have a complete octet (it only has 0 electrons), while Cl does.
- **Conclusion**: LiCl does not have a complete octet for the central atom (Li).

### Step 2: Analyze BeH2
- **Valence Electrons**: Beryllium (Be) has 2 valence electrons, and each Hydrogen (H) has 1 valence electron.
- **Bond Formation**: Be shares its 2 electrons with 2 H atoms (1 electron with each).
- **Electron Count**: Be shares 2 electrons, giving it a total of 4 electrons around it.
- **Octet Status**: Be does not have a complete octet (it only has 4 electrons).
- **Conclusion**: BeH2 does not have a complete octet for the central atom (Be).

### Step 3: Analyze BCl3
- **Valence Electrons**: Boron (B) has 3 valence electrons, and each Chlorine (Cl) has 7 valence electrons.
- **Bond Formation**: B shares its 3 electrons with 3 Cl atoms (1 electron with each).
- **Electron Count**: B shares 3 electrons, resulting in a total of 6 electrons around it.
- **Octet Status**: B does not have a complete octet (it only has 6 electrons).
- **Conclusion**: BCl3 does not have a complete octet for the central atom (B).

### Step 4: Analyze CO2
- **Valence Electrons**: Carbon (C) has 4 valence electrons, and each Oxygen (O) has 6 valence electrons.
- **Bond Formation**: C shares 4 electrons (2 with each O) resulting in double bonds with both O atoms.
- **Electron Count**: C shares 4 electrons, and each O shares 2 electrons, giving C a total of 8 electrons around it.
- **Octet Status**: C has a complete octet (8 electrons).
- **Conclusion**: CO2 has a complete octet for the central atom (C).

### Final Answer
The molecule that has a complete octet of the central atom is **CO2**.

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