Identify the following molecules as polar or nonpolar.

1. H2S
2. PBr3
3. SiCl4
4. SO2

Use the electronegativity chart to do these.

To identify whether a molecule is polar or nonpolar, you need to examine the molecular geometry and the polarity of its individual bonds.

1. H2S: The molecule has a bent or V-shaped geometry due to the presence of two lone pairs of electrons on the sulfur atom. The hydrogen and sulfur atoms have a significant difference in electronegativity. Since the molecule is bent and asymmetric, it is polar.

2. PBr3: The molecule has a trigonal pyramidal geometry with three Br atoms bonded to the central P atom. Bromine (Br) is more electronegative than phosphorus (P), resulting in polar covalent bonds. As a result, the molecule is polar.

3. SiCl4: The molecule has a tetrahedral geometry with four chlorine atoms bonded to the central silicon (Si) atom. Although chlorine is more electronegative than silicon, the molecule is symmetrical. Therefore, even though the bonds are polar, the polarities cancel out, making the molecule nonpolar.

4. SO2: The molecule has a bent or V-shaped geometry with two oxygen (O) atoms bonded to the central sulfur (S) atom. Oxygen is more electronegative than sulfur, leading to polar covalent bonds. The molecule is also asymmetrical, thus making it polar.