Please only respond if you can help, I need to pass

Which of the following observations indicates that there is a small, dense, positively charged part in the center of an atom? some uncharged particles are scattered by a gold foil. all uncharged particles are attracted towards a gold foil. all positively charged particles pass straight through a gold foil. some positively charged particles bounce back from a gold foil.

If anyone would be able to me out with these three questions it would be these are from the chem 2202 course.

What does the symbol (–hfus) indicate in a phase change?