Match List I (Scientist) with List II (Discovery) and select the correct answser using the codes given below the lists. List I A. Goldstein B. Chadwick C. JJ Thomson D. John Dalton List II 1. Atomic theory 2. Proton 3. Neutron 4. Electron Codes: ABCD

The discovery of subatomic particles and atomic theory followed a chronological progression. John Dalton formulated the first modern atomic theory in 1803, proposing that matter is composed of indivisible atoms. In 1886, Eugen Goldstein discovered canal rays, which were later identified as positive ions or protons. J.J. Thomson discovered the electron in 1897 through his experiments with cathode rays, proving that atoms were divisible. Finally, James Chadwick discovered the neutron in 1932, identifying it as a neutral particle with a mass similar to a proton. Matching these: A (Goldstein) with 2 (Proton), B (Chadwick) with 3 (Neutron), C (JJ Thomson) with 4 (Electron), and D (John Dalton) with 1 (Atomic theory) results in the sequence 2-3-4-1.