Carbon tetrachloride was formerly used in fire extinguishers for electrical fires. It is no longer used for this purpose because of the formation of the toxic gas phosgene, \(\mathrm{Cl}_{2}\) CO. Write the Lewis structures for carbon tetrachloride and phosgene.

Understanding the valence electrons of an atom is crucial when studying and predicting chemical bonding behaviors. Valence electrons are the electrons that reside in the outermost shell of an atom, and they play a pivotal role in the formation of chemical bonds. In the exercise provided, carbon (C) possesses 4 valence electrons which means it can form up to four bonds. Chlorine (Cl), with 7 valence electrons, seeks one more to complete its valence shell, while oxygen (O) with 6 valence electrons requires two more to fill its outer shell.

The interactions involving valence electrons are guided by the principles of chemical bonding, as seen in the Lewis structures for carbon tetrachloride and phosgene. In these examples, these outer electrons get shared or transferred between atoms, allowing the formation of molecules. Valence electrons dictate how atoms connect, and without understanding this concept, one cannot grasp the nuances of molecular structures.

Chemical bonding is the process where atoms combine to form molecules. There are several types of chemical bonds, including ionic, covalent, and metallic bonds. In our exercise, we focus on covalent bonds, where atoms share valence electrons to achieve stability. The Lewis structures in the exercise depict this sharing of electrons.In the case of carbon tetrachloride, carbon shares its four electrons with four chlorine atoms, leading to the formation of single covalent bonds. Phosgene presents a more complex scenario with a double bond between carbon and oxygen and single bonds between carbon and chlorine atoms. This variety in bonding types within a molecule can affect its physical and chemical properties, making the distinction and proper representation of these bonds essential to understanding its behavior.

The octet rule is a chemical tenet that asserts atoms are most stable when they have eight electrons in their valence shell. This rule is widely applicable to many elements, particularly the main-group elements, and drives the formation of chemical bonds. Both carbon tetrachloride and phosgene are examples of molecules where the central atom, carbon, follows the octet rule.Following the octet rule, each chlorine in carbon tetrachloride, as well as oxygen in phosgene, achieves an octet through the sharing of electrons with carbon. It's important to recognize exceptions to this rule, like molecules involving elements capable of having more than eight valence electrons (expanded octets), or those with less (incomplete octets). Nonetheless, the octet rule serves as a valuable guideline when predicting and drawing molecular structures such as the ones in this exercise.