The antibiotic thiarubin-A was discovered by studying the feeding habits of wild chimpanzees in Tanzania. The structure for thiarubin-A is a. Complete the Lewis structure showing all lone pairs of electrons. b. Indicate the hybrid orbitals used by the carbon and sulfur atoms in thiarubin-A. c. How many \(\sigma\) and \(\pi\) bonds are present in this molecule?

Before drawing the complete Lewis structure, we need to find the formula for the molecule. The thiarubin-A molecule has the molecular formula C_10H_12S_2O. 1. Write down the symbols for all the atoms in the molecule: C C C C C C C C C C H H H H H H H H H H S S O 2. Place the least electronegative atoms (usually the carbon atoms) in the center of the molecule and connect them with single bonds. 3. Add hydrogens to the carbons so that each carbon has a total of four bonds. The hydrogens will be placed on the end of each carbon with single bonds. 4. Add the oxygen atom by connecting it to one of the carbons with a double bond (C = O). 5. Finally, add two sulfur atoms, each connected with a double bond (C = S and S = C) to form thiarubin-A. Now, draw all lone pairs of electrons in thiarubin-A structure. Oxygen atom will have two lone pairs of electrons due to its double bond with carbon, and each sulfur atom will have one lone pair due to their double bonds with carbons.

We need to identify the hybridization state at the various atom positions in the thiarubin-A structure. 1. For each carbon atom, except the carbons bonded with sulfur and oxygen, determine the number of electron groups around the carbon (including bonds and lone pairs). Each carbon is tetrahedral with all single bonds, so it uses sp^3 hybrid orbitals. 2. For the carbons bonded directly to oxygen and sulfur atoms, they are involved in a double bond. Double bonding produces a trigonal planar arrangement, so these carbons use sp^2 hybrid orbitals. 3. For sulfur atoms, they are involved in double bonding with carbon atoms. The sulfur atoms have a lone pair and two electron groups involved in bonding, forming a trigonal planar arrangement. These sulfur atoms also use sp^2 hybrid orbitals. 4. Finally, for the oxygen atom, it forms a double bond with one carbon atom. As a result, the oxygen atom uses sp^2 hybrid orbitals.

To count the number of σ and π bonds, we need to analyze the bond types in the thiarubin-A structure. 1. Count the number of single bonds, these will be considered as σ bonds. There are a total of 21 single bonds in the molecule: 18 C-H bonds, 1 S-C bond, and 2 C-C bonds. 2. Count the number of double bonds. These will contribute to one σ bond and one π bond each. There are 3 double bonds in the molecule: 1 C=O bond and 2 C=S bonds. Therefore, the total number of σ bonds is 21 (from single bonds) + 3 (from double bonds) = 24. The total number of π bonds is 3 (from double bonds). So, there are 24 σ bonds and 3 π bonds in the thiarubin-A molecule.