https://www.khanacademy.org/science/chemistry/atomic-structure-and-properties/history-of-atomic-structure/v/chem37-history-of-atomic-chemistry 2021-01-04T18:35:18Z The history of atomic chemistry How did we get here? Well, in terms of Atomic Chemistry, Hank takes us on a tour of the folks that were part of the long chain of other folks who helped us get to these deeper understandings of the world. From Leucippus to Heisenberg to you - yes, YOU - the story of Atomic Chemistry is all wibbly-wobbly... and amazing. Writers: Edi Gonzalez Chief Editor: Blake de Pastino Consultant: Dr. Heiko Langner Director/Editor: Nicholas Jenkins Sound Designer: Michael Aranda Graphics: Thought Cafe EcoGeek video https://cdn.kastatic.org/googleusercontent/GO0u9HHdzI9kJNS_UiKwqEtCxd22caj9EbDfYDXkJiVfWzeJSOSOSkH60yAgyvmTtVayrfLXSZA9wmFYIEna177WYg The history of atomic chemistry How did we get here? Well, in terms of Atomic Chemistry, Hank takes us on a tour of the folks that were part of the long chain of other folks who helped us get to these deeper understandings of the world. From Leucippus to Heisenberg to you - yes, YOU - the story of Atomic Chemistry is all wibbly-wobbly... and amazing. Writers: Edi Gonzalez Chief Editor: Blake de Pastino Consultant: Dr. Heiko Langner Director/Editor: Nicholas Jenkins Sound Designer: Michael Aranda Graphics: Thought Cafe https://cdn.kastatic.org/ka-youtube-converted/agjG7kgixJs.mp4/agjG7kgixJs.mp4 527 Atom 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 Atom https://www.khanacademy.org/science/mh-grade-8-science/x0f256b8de9c7cf34:inside-the-atom/x0f256b8de9c7cf34:atomic-models/e/lo-3-2-atomic-models 2026-06-15T04:30:38.969568377Z Atomic models Let's solve some problems to better understand the various atomic models proposed by different scientists. Aakash Bagga exercise 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/cambridge-o-level-physics-cie/x0e04e0cb682fb793:nuclear-physics/x0e04e0cb682fb793:the-atom/a/discovery-of-the-electron-and-nucleus 2021-07-18T18:44:33.041351326Z Discovery of the electron and nucleus Thomson's cathode ray experiment and Rutherford's gold foil experiment article https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:atoms-isotopes-and-ions/x2613d8165d88df5e:atomic-structure/v/protons-neutrons-and-electrons-in-atoms 2025-11-01T06:31:04.963641538Z Protons, neutrons, and electrons in atoms Atoms are made up of three types of subatomic particles: protons, neutrons, and electrons. Protons and neutrons are found in the nucleus, the dense region at the center of an atom. Electrons are found outside the nucleus. Protons are positively charged and have a mass of about 1 u. Neutrons are neutral (have no charge) and also have a mass of about 1 u. Electrons are negatively charged and have a much smaller mass of about 0.0005 u. Wieteke Holthuijzen video https://cdn.kastatic.org/ka_thumbnails_cache/b0e49086-7776-4d8b-8b13-7afbfd62b856_1280_720_base.png Protons, neutrons, and electrons in atoms Atoms are made up of three types of subatomic particles: protons, neutrons, and electrons. Protons and neutrons are found in the nucleus, the dense region at the center of an atom. Electrons are found outside the nucleus. Protons are positively charged and have a mass of about 1 u. Neutrons are neutral (have no charge) and also have a mass of about 1 u. Electrons are negatively charged and have a much smaller mass of about 0.0005 u. https://cdn.kastatic.org/ka-youtube-converted/lz_gMkQr7YE.mp4/lz_gMkQr7YE.mp4 151 Atom https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:atoms-isotopes-and-ions/x2613d8165d88df5e:atomic-structure/e/apply-atomic-structure 2026-06-25T14:10:39.916233732Z Apply: Atomic structure Apply your understanding of atomic structure in this set of free, standards-aligned practice questions. Megan Cohn exercise https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:nuclear-physics/x0e04e0cb682fb793:the-atom/e/atomic-structure 2026-04-03T18:30:01.793877038Z Atomic structure Test your knowledge of atomic structure! Ashley exercise