Predict whether each of the following molecules is polar or nonpolar: (a) IF, (b) CS2, (c) SO3, (d) PCl3, (e) SF6, (f) IF5.

Key Concepts

Molecular Polarity

Molecular polarity refers to the distribution of electrical charge across a molecule, which determines whether it has a positive or negative end. A molecule is polar if it has a significant difference in electronegativity between its atoms, leading to an uneven distribution of charge. Nonpolar molecules, on the other hand, have an even distribution of charge, often due to symmetrical arrangements of identical atoms or balanced dipoles.

Electronegativity

Electronegativity is a measure of an atom's ability to attract and hold onto electrons in a chemical bond. The difference in electronegativity between two bonded atoms can indicate whether the bond is ionic, polar covalent, or nonpolar covalent. In general, larger differences in electronegativity (greater than 1.7) result in ionic bonds, while smaller differences (less than 1.7) can lead to polar or nonpolar covalent bonds.

Molecular Geometry

Molecular geometry refers to the three-dimensional arrangement of atoms within a molecule. The shape of a molecule affects its polarity; for example, a symmetrical shape can lead to nonpolar characteristics even if the individual bonds are polar. Understanding the geometry, often predicted by VSEPR theory, is crucial for determining the overall polarity of a molecule, as it influences how dipoles from polar bonds interact.