https://www.khanacademy.org/science/mh-grade-8-science/x0f256b8de9c7cf34:inside-the-atom/x0f256b8de9c7cf34:atomic-models/a/daltons-atomic-theory-version-2 2021-04-29T07:55:47Z Dalton's atomic theory The postulates of Dalton's atomic theory: which points do we still use today, and what have we learned since Dalton? article https://www.khanacademy.org/science/grade-9-chemistry-snc-aligned/x22d5b83c2ea2dc38:atomic-structure/x22d5b83c2ea2dc38:discovery-of-sub-atomic-particles/v/discovery-of-electrons-pk 2025-12-31T05:23:06.848711158Z Discovery of electrons How were electrons discovered? In this video, we explore the experiment that led to the discovery of the electron, and the key observations that changed atomic theory forever. We’ll walk you through J.J. Thomson’s cathode ray experiment, the effects of electric and magnetic fields on the rays, and how these findings revealed the presence of negatively charged particles. This isn’t just a history lesson, it’s a step-by-step breakdown of how careful observation and clever experimentation unlocked the subatomic world. Khan Academy video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Discovery of electrons How were electrons discovered? In this video, we explore the experiment that led to the discovery of the electron, and the key observations that changed atomic theory forever. We’ll walk you through J.J. Thomson’s cathode ray experiment, the effects of electric and magnetic fields on the rays, and how these findings revealed the presence of negatively charged particles. This isn’t just a history lesson, it’s a step-by-step breakdown of how careful observation and clever experimentation unlocked the subatomic world. https://cdn.kastatic.org/ka-youtube-converted/HipvMKhgl5M.mp4/HipvMKhgl5M.mp4 291 Atomic theories https://www.khanacademy.org/science/chemistry/atomic-structure-and-properties/history-of-atomic-structure/v/rutherfords-gold-foil-experiment 2022-09-27T05:27:31.474935863Z Rutherford’s gold foil experiment Learn about Rutherford's discovery of the nucleus and the development of the nuclear model of the atom. video https://cdn.kastatic.org/googleusercontent/GUca1q02zeVjSuVtBIXH6p52GSGoDXIJ1yEl6cYQ4J1y8JlCk2lZbfkLapmLiIsRJkG0n-vitdeSdc31H9toW26p Rutherford’s gold foil experiment Learn about Rutherford's discovery of the nucleus and the development of the nuclear model of the atom. https://cdn.kastatic.org/ka-youtube-converted/bVlwH1kfDeg.mp4/bVlwH1kfDeg.mp4 684 Atomic theories https://www.khanacademy.org/science/grade-7-science-cambridge-curriculum/x754b285620daf71e:structure-of-an-atom/x754b285620daf71e:atomic-theories/v/rutherford-scattering-experiment-atoms 2026-04-30T07:30:36.209464894Z Rutherford scattering experiment - Atoms Rutherford scattering experiment Khan Academy Pakistan video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Rutherford scattering experiment - Atoms Rutherford scattering experiment https://cdn.kastatic.org/ka-youtube-converted/hJzgArYuF1k.mp4/hJzgArYuF1k.mp4 135 Atomic theories https://www.khanacademy.org/science/grade-9-chemistry-snc-aligned/x22d5b83c2ea2dc38:atomic-structure/x22d5b83c2ea2dc38:bohrs-atomic-model/v/drawback-of-the-rutherford-model-pk 2025-12-31T05:23:06.848711158Z Drawback of the Rutherford model What are the drawbacks of the Rutherford model? Let's find out! Khan Academy video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Drawback of the Rutherford model What are the drawbacks of the Rutherford model? Let's find out! https://cdn.kastatic.org/ka-youtube-converted/WDJyxY6Scvk.mp4/WDJyxY6Scvk.mp4 223 Atomic theories https://www.khanacademy.org/science/grade-7-science-cambridge-curriculum/x754b285620daf71e:structure-of-an-atom/x754b285620daf71e:atomic-theories/v/bohr-s-model-of-an-atom-atomic-theories 2026-04-30T07:30:36.209464894Z Bohr s model of an atom- Atomic theories Bohr s model of an atom Khan Academy Pakistan video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Bohr s model of an atom- Atomic theories Bohr s model of an atom https://cdn.kastatic.org/ka-youtube-converted/hAuAhJ7uQuM.mp4/hAuAhJ7uQuM.mp4 130 Atomic theories https://www.khanacademy.org/science/grade-7-science-cambridge-curriculum/x754b285620daf71e:structure-of-an-atom/x754b285620daf71e:atomic-theories/e/structure-of-atom-in 2026-04-07T23:36:17.218592739Z Structure of atom Let's practice! vibhor exercise