Question

Two different molecules have the formula \(\mathrm{C}_{2} \mathrm{H}_{2} \mathrm{Cl}_{2}\). Draw a Lewis structure for each molecule. (All the \(\mathrm{H}\) and \(\mathrm{Cl}\) atoms are bonded to carbon. The two carbon atoms are bonded to each other.)

Short answer

The two possible Lewis structures for the given molecular formula are: 1. In the first structure, a hydrogen atom and a chlorine atom are bonded to each carbon atom, with a double bond between the two carbon atoms: ``` H H | | Cl -- C == C -- Cl ``` 2. In the second structure, both chlorine atoms are bonded to one carbon atom, and both hydrogen atoms are bonded to the other carbon atom, with a double bond between the two carbon atoms: ``` H Cl | | H -- C == C -- Cl ``` These two structures fulfill the requirements given in the problem.

Step-by-step solution

Understand Lewis structure

The Lewis structure is a graphical representation of the molecule where the atoms are represented by their chemical symbols, and the chemical bonds are represented by lines. The electrons that are involved in the formation of a chemical bond are called "valence electrons," and the Lewis structure helps us visualize the arrangement of these valence electrons around atoms in a molecule.

Identify the valence electrons

For this formula, we have two carbon atoms (C), two hydrogen atoms (H), and two chlorine atoms (Cl). Their valence electrons are as follows: - Carbon (C) has 4 valence electrons (from group 14 in the periodic table). - Hydrogen (H) has 1 valence electron (from group 1 in the periodic table). - Chlorine (Cl) has 7 valence electrons (from group 17 in the periodic table).

Draw the first Lewis structure

In the first structure, we will place a hydrogen atom and a chlorine atom on each carbon atom. The two carbon atoms are bonded to each other, and the bonds between them involve the sharing of two pairs of electrons. This is a double bond. Here is the Lewis structure: ``` H H | | Cl -- C == C -- Cl ```

Draw the second Lewis structure

In the second structure, we will place both chlorine atoms on one carbon atom and both hydrogen atoms on the other carbon atom. The two carbon atoms again form a double bond. Here is the Lewis structure: ``` H Cl | | H -- C == C -- Cl ``` These are the two possible Lewis structures for the molecule \(\mathrm{C}_{2} \mathrm{H}_{2} \mathrm{Cl}_{2}\). Keep in mind that there might be other structures as well, but the ones shown here fulfill the requirements given in the exercise.