Thats allllllll otttt but ill help
step by step
Answer:
part a=A. A physical change, then a chemical change
part b:evidence
without physical change any sorts of chemical change do not take place.
for example: when sugar is heated on spoon the physical change takes place in sugar .sugar starts to form liquid from solid.
Answer: Electronic transition moments are defined as the probability for a given excitation energy transition to take place. It should be evident that the transition moment depends upon the spin-orbit coupling of the electrons in both the ground and excited states.