Challenge question: This question is worth 6 points. As you saw in problem 9 we can have species bound to a central metal ion. These species are called ligands. In the past we have assumed all the d orbitals in some species are degenerate; however, they often are not. Sometimes the ligands bound to a central metal cation can split the d orbitals. That is, some of the d orbitals will be at a lower energy state than others. Ligands that have the ability to cause this splitting are called strong field ligands, CN− is an example of these. If this splitting in the d orbitals is great enough electrons will fill low lying orbitals, pairing with other electrons in a given orbital, before filling higher energy orbitals. In question 7 we had Fe2+, furthermore we found that there were a certain number (non-zero) of unpaired electrons. Consider now Fe(CN)6 4−: here we also have Fe2+, but in this case all the electrons are paired, yielding a diamagnetic species. How can you explain this?

Why is the bond angle in a water molecule less than the bond angle of methane? a. the central oxygen atom in water has two lone pairs of electrons, whereas the central carbon atom in methane has no lone pairs. b. the central hydrogen atom in water has one lone pair of electrons, whereas the central carbon atom in methane has two lone pairs. c. the central oxygen atom in water has four lone pairs of electrons, whereas the central carbon atom in methane has only one lone pair. d. the central oxygen atom exerts more repulsive force on surrounding atoms than the central carbon atom in methane does. reset next

98 points you will be galileo perform the experiment to determine if objects with different mass fall at the same, or different, rates in the air and in a vacuum. before you conduct your experiment, you need to form a hypothesis. a hypothesis is a prediction of what you think will happen in the experiment. the hypothesis is a statement that describes “if” a certain set of circumstances are present “then” there will be a specific result that will occur. record your hypothesis here: record the results from step one of the experiment (dropping the objects in the air): first trial: second trial: third trial: record the results from step two of the experiment (dropping the objects in a vacuum): first trial: second trial: third trial: did the experiment support your hypothesis? using the data from your experiment, describe why you believe your hypothesis was either proven or disproven. what forces were acting on the objects dropped in the air? what force was acting on the objects dropped in the vacuum? part two: comparing forces choose two forces and compare and contrast these forces. you must provide two ways that they are alike and two ways that they are different. you may make a list, write in paragraph form, or make a chart. choose two forces and compare and contrast these forces. these must be different forces than used in the prior question. provide two ways that they are similar and two ways that they are different. you may make a list, write it out, or make a chart.

What is the binding energy of a nucleus that has a mass defect of 5.81*10-^29 kg a 5.23*10-^12 j b 3.15* 10^12 j c 1.57*10-3 j d 9.44*10^20 j