Millikan determined the charge on the electron by studying the static charges on oil drops falling in an electric field. A student carried out this experiment using several oil drops for her measurements and calculated the charges on the drops. She obtained the following data: Droplet Calculated Charge(C) A 1.60 ✕10-19 B 3.15 ✕10-19 C 4.81 ✕10-19 D 6.31 ✕10-19 A. What is the significance of the fact that the droplets carried different charges? [4 marks] B. What conclusion can the student draw from these data regarding the charge of the electron? [4 marks] C. What value (and to how many significant figures) should she report for the electronic charge? [4 marks] Question 2: Use VSEPR theory to predict the molecular shape and the polarity of SF2. Explain your answer. [4 marks] Question 3: Draw a Lewis structure for PCl4 . Use VSEPR theory to predict the molecular shape of this ion.?

Goldenman34

2 years ago

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Question 1:
A. The significance of the fact that the droplets carried different charges indicates that the oil drops had different numbers of excess electrons. This variation in charge suggests that the oil droplets had different numbers of individual electrons attached to them, which could result from variations in the sizes and masses of the oil droplets or variations in the number of excess electrons they acquired during the experiment.

B. From the data, the student can draw the conclusion that the charges calculated for the oil droplets are all multiples of a fundamental unit of charge. This implies that the charges on the droplets are quantized, indicating that the charges on the oil droplets are composed of a discrete number of individual elementary charges, which supports Millikan's determination of the charge of the electron.

C. The student should report the electronic charge as the smallest common multiple of the calculated charges on the oil droplets. Looking at the data, the smallest common multiple of the calculated charges is \(1.60 \times 10^{-19}\) C, which is the charge of the electron. Thus, the electronic charge should be reported as \(1.60 \times 10^{-19}\) C.

Question 2:
Using VSEPR theory, SF2 has a molecular shape of bent or angular. This is because sulfur (S) has two bonded pairs and one lone pair of electrons, resulting in a trigonal planar electron geometry. However, due to the lone pair-bond pair repulsion, the two fluorine (F) atoms are pushed closer together, causing the molecular shape to be bent. SF2 is polar because the sulfur-fluorine bonds are polar due to the difference in electronegativity between sulfur and fluorine, and the bent molecular geometry results in an overall dipole moment.

Question 3:
The Lewis structure for PCl4- is drawn with one phosphorus (P) atom in the center bonded to four chlorine (Cl) atoms, with one lone pair on the phosphorus atom. The molecular shape of PCl4- is tetrahedral, as it has four bonded pairs and one lone pair of electrons around the central atom.