The quantum mechanical approach to atomic structure permits the calculation of 1. the most probable distance between any two specified electrons. 2. a region about the nucleus in which an electron of specified energy will probably be found. 3. the most probable radius of an orbit that an electron of specified energy will follow. 4. the most probable spin value that will be associated with an electron of specified energy. 5. the number of electrons in an atom.

You have two photos of a person walking. one shows the person at the corner of third and main streets, the other shows the person at the corner of tenth and main streets. there are lampposts at every corner in this town, and the first picture shows it to be 10: 32: 00 exactly. the second picture shows it to be 10: 49: 30. you know three facts: (1) all of the clocks are synchronized; (2) there are exactly 12 equal-sized blocks per kilometer in this town; and (3) the streets that cross main in this area are numbered consecutively, with no interruptions. what is the person’s average speed in kilometers per hour?