The model of the adam has changed over time in light of new knowledge and discoveries. which option correctly describes one such change. 1. about 1915 jj thomas developed an atomic model where negatively charged particles orbit a positively charged nucleus. 2. in 420 bc john dalton developed the idea that small atoms combine to form molecules. 3. about 1900 j. j. thomas discovered electrons were negatively charged particles. 4. about 1900 niels bohr developed an atomic model where positively charged particles orbit a negatively charged nucleus.