Question

(a) Does \(\mathrm{SCl}_{2}\) have a dipole moment? If so, in which direction does the net dipole point? (b) Does \(\mathrm{BeCl}_{2}\) have a dipole moment? If so, in which direction does the net dipole point?

Short answer

(a) \(\mathrm{SCl}_{2}\) has a dipole moment and the net dipole points towards the Chlorine atoms. (b) \(\mathrm{BeCl}_{2}\) does not have a dipole moment.

Step-by-step solution

Determine the molecular structure of \(\mathrm{SCl}_{2}\) and \(\mathrm{BeCl}_{2}\)

The first thing we need to do is draw the Lewis structures of the two given molecules. This will help us determine their geometrical shapes. For \(\mathrm{SCl}_{2}\), Sulfur has 6 valence electrons and each Chlorine has 7 valence electrons, which means that there are a total of 20 valence electrons in the molecule. The Lewis structure is as follows: Sulfur is connected to two Chlorine atoms with single bonds, and there are 2 lone pairs of electrons on the Sulfur atom. Due to two bonding pairs and two lone pairs, the molecular geometry of \(\mathrm{SCl}_{2}\) is V-shaped or bent. For \(\mathrm{BeCl}_{2}\), Beryllium has 2 valence electrons and each Chlorine has 7 valence electrons, which means that there are a total of 16 valence electrons in the molecule. The Lewis structure is as follows: Beryllium is connected to two Chlorine atoms with single bonds, and there are no lone pairs of electrons on the Beryllium atom. Due to two bonding pairs and no lone pairs, the molecular geometry of \(\mathrm{BeCl}_{2}\) is linear.

Analyze the electronegativity differences in \(\mathrm{SCl}_{2}\) and \(\mathrm{BeCl}_{2}\)

Now that we know the geometries of both molecules, we can analyze the electronegativity differences between the atoms. Electronegativity increases across a period from left to right (excluding noble gases), and it decreases down a group. For \(\mathrm{SCl}_{2}\), Chlorine is more electronegative than Sulfur, so it will pull the electrons in the bond closer to itself, creating a bond dipole. In \(\mathrm{BeCl}_{2}\), Chlorine is also more electronegative than Beryllium, so there will also be a bond dipole here.

Determine if there is a net dipole moment in \(\mathrm{SCl}_{2}\) and \(\mathrm{BeCl}_{2}\), and the direction of the net dipole

For \(\mathrm{SCl}_{2}\), the molecule has a bent geometry, and since Chlorine is more electronegative than Sulfur, it will create two bond dipoles pointing towards the Chlorine atoms. Due to the bent geometry, these dipoles don't cancel each other out and therefore, there is a net dipole moment in the molecule. The direction of the net dipole is towards the Chlorine atoms. For \(\mathrm{BeCl}_{2}\), the molecule has a linear geometry, and the bond dipoles are pointing in opposite directions. Due to the symmetry of the molecule, the bond dipoles cancel each other out, resulting in no net dipole moment in the molecule. #Answer# (a) \(\mathrm{SCl}_{2}\) has a dipole moment and the net dipole points towards the Chlorine atoms. (b) \(\mathrm{BeCl}_{2}\) does not have a dipole moment.