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.
Rutherford suggested the atom had a dense positively charged nucleus which occupied little space and that there was much empty space in the atom where the elctrons floated in a circle around the nucleus///Bohr suggested that there were rings which each held a specific amout of electrons and were held together by the force of attraction.