—It has been found that, if an electrically charged particle revolves around the circular path, then it radiates out energy. Thus if an electron moves around the nucleus, it must continuously radiate out energy, and hence gradually moves towards nucleus in a spiral path, till it collides with nucleus. However, we know that atom is stable. Rutherford's model can't explain this stability.
—Rutherford's model of atom does not say anything about the arrangement of electrons in an atom.