CHM 25500 Final: Organic Chemistry_Final Exam Study Guide [Helped Me Get An A!]

Quantum mechanics is a very complex theory. A good way to help you remember it is to compare it to an apartment building. An apartment building has different floors, different apartments on each floor, and different rooms within each apartment. We can look upon the electrons of an atom as rather peculiar apartment dwellers. Electrons prefer the floor closest to the ground and the smallest apartments. Electrons also prefer to live one to a room until each room in an apartment has one occupant. The electrons will then pair up until each room has two. Each room in an apartment can hold two electrons Apartment buildings have several floors. The model we discuss has several floors, but only the first 7 floors will be occupied. All the electrons known today will fit within 7 floors of the building. Additional floors are available but will only be occupied in special situations. The floors in the apartment building are called shells in the electron model and are numbered 1-7. 1) According to what you have just read, what shell will be occupied first by electrons? 2 flers Each shell (or floor) in the model has one or more apartments, which are called subshells. These subshells are apartments of four sizes: s,p,d, and f. An s subshell (apartment) has only a single room. A p subshell has 3 rooms. A d subshell has 5 rooms, while an fsubshell has 7 rooms. An s subshell then will hold a maximum of 2 electrons according to the model. 2) A p subshell will bold a maximum of how many electrons? 3) How many will a d subshell hold? lo e lect@n)、.」 4) How many will an fsubshell hold? Iy cles tiou Each room in a subshell is called an orbital. From the previous question we know that a s subshell will consist of one orbital with a capacity (occupancy) of 2 electrons. 5) A p subshell will consist of 3 orbitals with a total subshell capacity of electrons. 6) A d subshell will have 7) Anf subshell will have orbitals and a total capacity of lo_ electrons orbi electrons. The first shell (floor) has only 1 subshell (apartment), which is an s subshell Because of its location on the first shell, it is called a ls subshell 8) How many orbitals(rooms) are there in the Is subshell? 9) How many electrons will the subshell hold?-- a. The second shell (floor) only has an s subshell (apartment) and a p subshell 10) If the s subshell is called 2, what do you suppose the p subshell is called? 11) How many orbitals (rooms) are in that p subshell? 12) How many subshells are in the second shell? 13) How many orbitals are there in the second shell? 14) How many electrons can occupy the second shell? 15) The third shell has 3 subshells: s.p andd 16) What are they called? 17) How many subshells are in the third shell? 18) How many orbitals are in the third shell?

th Q4A: Draw a molecule that is capable of undergoing an electrocyclization reaction, in which the product has two chiral spstrocenters, Then, draw the mechanism and product(s) of for a photochemically induced electrocyclization reaction of your molecule. Q4B: Now, draw a diagram showing all of the frontier MO of your reactant from Q2A and place the electrons in these MO in the ground state. We commonly use a combination of p orbitals to represent the MOs, complete with different lobes colored/shaded differently and nodes (example shown). We use additional horizontal lines to represent the energy levels for the different MOs and arrows to indicate presence of electrons in these MOs and energy levels (please see textbook or lecture slides for examples of these drawings). Use the labels HOMO p orbital and LUMO if appropriate. Q4C: Now imagine your molecule has light shine upon it (i.e. is irradiated), and the characteristic of the light energy is sufficient to be absorbed by your molecule. This puts your molecule into a higher energy, excited state. Draw an accompanying diagram that shows the changes to the electrons in your frontier MO diagram upon photo excitation. Use the labels HOMO and LUMO if appropriate. Q4D: On your diagram in Q2C (photoexcited state), draw a line that connects the two lobes of the appropriate MOs that will combine to make the new sigma bond that forms during the electrocyclization reaction. Q4E: Based on Q2D, will your reaction go through a disrotatory or conrotatory mechanism? Q4F: Could your reaction produce more than one stereoisomers? lobes shaded differently ith different lobeuntl of the frontier auedelectroction