When you were young you may have had your own theory about why plants are green. Then, as you learned more, you kept ideas that were correct, but replaced ideas that were incorrect. Atomic theory also changed as scientists improved their understanding. What incorrect idea in Bohr’s understanding of the atom was replaced in later theories? A. Atoms cannot be divided. B. An atom is mostly empty space. C. In an atom, electrons orbit the nucleus like planets orbit the sun. D. An atom includes electrons embedded in a sphere of positive charge.