What do they look like? Tree swallows are small birds (about 14 cm long) with long wings and small legs and feet. They are irridescent greenish-blue on their head, shoulders and back, and white their chin, breast and belly. Tree swallows have a short black beak and dark brownish feet.
Ernest Rutherford concluded that an atom contains a very small, dense center, called a nucleus, with a positive charge as a result of his gold foil experiment.
B. There is a small, dense, positively charged nucleus. C. There are small, negatively charged particles inside an atom. D. Electrons can jump from a path in one level to a path in another level. E. Atoms of different elements are different.