Question

Which of the following molecules contain polar covalent bonds? a. carbon monoxide, CO b. chlorine, \(\mathrm{Cl}_{2}\) c. iodine monochloride, ICl d. phosphorus, \(\mathrm{P}_{4}\)

Short answer

Based on the electronegativity differences, the molecules containing polar covalent bonds are carbon monoxide (CO) and iodine monochloride (ICl).

Step-by-step solution

Electronegativity Values

To determine the polarity, we need to know the electronegativity values. Here are the electronegativity values of the involved atoms: Carbon (C): 2.5 Oxygen (O): 3.4 Chlorine (Cl): 3.2 Iodine (I): 2.7 Phosphorus (P): 2.2

Determine Electronegativity Differences

Now, calculate the electronegativity differences for each molecule: a. CO: \(|3.4 - 2.5| = 0.9\) b. \(\mathrm{Cl}_{2}\): \(|3.2 - 3.2| = 0\) c. ICl: \(|3.2 - 2.7| = 0.5\) d. \(\mathrm{P}_{4}\): \(|2.2 - 2.2| = 0\)

Determine Polar Covalent Bonds

Based on the electronegativity differences calculated in Step 2, determine if each bond is polar covalent or not (Electronegativity difference between 0.4 and 1.7): a. CO: 0.9, Polar Covalent b. \(\mathrm{Cl}_{2}\): 0, Non-polar Covalent c. ICl: 0.5, Polar Covalent d. \(\mathrm{P}_{4}\): 0, Non-polar Covalent Conclusion: Molecules with polar covalent bonds: carbon monoxide (CO) and iodine monochloride (ICl).

Key concepts

Electronegativity

Electronegativity plays a pivotal role in determining the kind of bond two atoms will form. Defined as the measure of an atom's ability to attract and hold onto electrons, electronegativity values vary across the periodic table. Generally, electronegativity increases from left to right and decreases from top to bottom.
Elements with high electronegativity, such as oxygen or fluorine, tend to attract electrons more strongly than those with low electronegativity, like cesium or francium. This ability to pull electrons towards itself can result in unequal sharing when these atoms are linked to others with differing electronegativity. For example, in the molecule carbon monoxide (CO), oxygen has a greater electronegativity than carbon, resulting in a polar covalent bond.

Molecular Polarity

Understanding molecular polarity is key to grasping how molecules interact with each other and with other substances. Molecular polarity is dependent on both the individual bond polarities within a molecule and the shape of the molecule. Polar covalent bonds occur when there is an unequal sharing of electrons between atoms, due to a significant difference in their electronegativities.
A molecule is considered polar if it has a net dipole moment, which is a measure of the overall charge separation within the molecule. For instance, in iodine monochloride (ICl), the bond is polar because of the difference in electronegativity between iodine and chlorine, creating a molecule with one end slightly positive and the other end slightly negative. However, molecular polarity is not just about individual bond polarity; the three-dimensional arrangement of bonds also affects the overall polarity of the molecule.

• A symmetrical molecule with polar bonds might still be nonpolar if the polarities cancel each other out.
• A molecule with an asymmetrical shape and polar bonds is often polar because the dipoles do not cancel.

Chemical Bonding

Chemical bonding is the force that holds atoms together in molecules. It's essential for constructing everything from simple compounds, like water, to complex proteins that make up living organisms. There are three primary types of chemical bonds: ionic, covalent, and metallic.
- Ionic bonds form between metals and non-metals when electrons are transferred from one atom to another, resulting in oppositely charged ions that attract each other.- Covalent bonds result from the sharing of electrons between non-metals. These can be either non-polar, where electrons are shared equally, or polar covalent, where one atom attracts the shared electrons more strongly due to a higher electronegativity.- Metallic bonds are found in metals, where electrons are delocalized across a lattice of metal cations.
In the context of the textbook exercise, polar covalent bonding is highlighted. For instance, carbon monoxide (CO) exhibits polar covalent bonding as the shared electrons are unequally distributed between carbon and oxygen because of the notable difference in their electronegativities.