Lewis structure for PH2Cl

The Correct Answer and Explanation is:

To draw the Lewis structure for PH2Cl (phosphine chloride), follow these steps:

Step 1: Count the Total Number of Valence Electrons

Phosphorus (P) is in group 15, so it has 5 valence electrons.
Hydrogen (H) is in group 1, so each H atom contributes 1 electron. There are 2 hydrogens, so they contribute 2 electrons in total.
Chlorine (Cl) is in group 17, so it has 7 valence electrons.

Thus, the total number of valence electrons is:5(P)+2×1(H)+7(Cl)=14 valence electrons.5 (P) + 2 \times 1 (H) + 7 (Cl) = 14 \text{ valence electrons.}5(P)+2×1(H)+7(Cl)=14 valence electrons.

Step 2: Arrange the Atoms

Phosphorus (P) is the central atom because it is less electronegative than chlorine (Cl) and can form more bonds.
Place the two hydrogens (H) and the chlorine (Cl) atoms around phosphorus.

Step 3: Connect Atoms with Single Bonds

Place a single bond (one shared pair of electrons) between phosphorus and each of the hydrogen atoms, and another single bond between phosphorus and chlorine. This uses 6 electrons (3 bonds × 2 electrons per bond).

Step 4: Distribute Remaining Electrons

After forming the 3 single bonds, there are 8 electrons remaining (14 total – 6 used in bonding).
These remaining electrons should be placed as lone pairs around the atoms. Since chlorine is more electronegative, it will take 3 lone pairs (6 electrons). This satisfies chlorine’s octet.
The remaining 2 electrons go as a lone pair on phosphorus.

Step 5: Check for Octets

Phosphorus has 3 bonds (6 electrons) and 1 lone pair (2 electrons), giving it 8 electrons around it, fulfilling the octet rule.
Hydrogen atoms are each bonded to phosphorus with a single bond, giving each hydrogen 2 electrons, which satisfies the duet rule for hydrogen.
Chlorine has 3 lone pairs (6 electrons) and 1 bond (2 electrons), giving it 8 electrons, fulfilling the octet rule for chlorine.

Final Lewis Structure:

The final structure for PH2Cl is:

   H
     |
H - P - Cl
     |
     lone pair on P

In summary:

Phosphorus (P) forms 3 bonds: one with each hydrogen and one with chlorine.
Chlorine (Cl) has 3 lone pairs and 1 bond to phosphorus.
Hydrogen (H) atoms each form a single bond with phosphorus and have no lone pairs.
The structure satisfies the octet rule for chlorine and phosphorus and the duet rule for hydrogen.