https://www.khanacademy.org/science/revision-odisha-class-7-sciencein/x65716bffe06ac65c:week-1/x65716bffe06ac65c:matter/v/introduction-to-atoms-and-molecules 2025-03-06T03:23:19.512752417Z Introduction to Atoms and Molecules Learn how atoms, the smallest unit of matter, combine to form elements like gold or molecules like oxygen and water. Discover the difference between molecules of elements (e.g., O₂, H₂) and compounds (e.g., H₂O) and how they represent the building blocks of everything around us. Shankar Nair video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Introduction to Atoms and Molecules Learn how atoms, the smallest unit of matter, combine to form elements like gold or molecules like oxygen and water. Discover the difference between molecules of elements (e.g., O₂, H₂) and compounds (e.g., H₂O) and how they represent the building blocks of everything around us. https://cdn.kastatic.org/ka-youtube-converted/EXCa58rcIKc.mp4/EXCa58rcIKc.mp4 353 Structure of Atom https://www.khanacademy.org/science/mh-grade-8-science/x0f256b8de9c7cf34:inside-the-atom/x0f256b8de9c7cf34:atomic-models/v/rutherford-scattering-experiment 2023-07-03T13:44:16.33096147Z Rutherford scattering experiment Rutherford discovered the structure of the atom! Let's understand his model through a simple activity! Vibhor Pandey video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Rutherford scattering experiment Rutherford discovered the structure of the atom! Let's understand his model through a simple activity! https://cdn.kastatic.org/ka-youtube-converted/CpF5evgsKYg.mp4/CpF5evgsKYg.mp4 135 Structure of Atom https://www.khanacademy.org/science/mh-grade-8-science/x0f256b8de9c7cf34:inside-the-atom/x0f256b8de9c7cf34:atomic-models/e/lo-3-1-constituents-of-atom-and-their-charge 2025-06-26T08:56:38.363651408Z Constituents of atom and their charge Let's solve some problems to better understand what is inside the atom and the charge of it's constituent particles. Aakash Bagga exercise https://www.khanacademy.org/science/grade-6-science-snc-aligned/x19bc096754f0b9af:elements-and-compounds/x19bc096754f0b9af:elements-atoms-and-molecules/e/atoms-molecules 2026-04-07T23:55:07.30621384Z Atoms & Molecules Lets answer some questions! Shankar R exercise https://www.khanacademy.org/science/mh-grade-8-science/x0f256b8de9c7cf34:inside-the-atom/x0f256b8de9c7cf34:atomic-models/e/lo-3-2-atomic-models 2026-04-07T23:17:37.123726494Z 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/bmc-grade-9-science/x345505a97fc4a662:measurement-of-matter/x345505a97fc4a662:atoms-and-molecules/v/worked-example-atomic-weight-calculations 2025-05-29T08:44:44.739717086Z Worked example: Atomic weight calculations Let's learn how to calculate atomic weight from atomic mass and percent abundance of carbon isotopes. Dubverse video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Worked example: Atomic weight calculations Let's learn how to calculate atomic weight from atomic mass and percent abundance of carbon isotopes. https://cdn.kastatic.org/ka-youtube-converted/3CYWrAZ4hME.mp4/3CYWrAZ4hME.mp4 267 Structure of Atom https://www.khanacademy.org/science/strengthened-shs-chemistry-1/x174677b2bfa4bea2:1st-quarter/x174677b2bfa4bea2:examples-of-isotopes/v/worked-example-identifying-isotopes-and-ions-dubv 2025-05-29T08:44:44.739717086Z Worked example: Identifying isotopes and ions Let's figure out how to identify isotopes and ions from the number of electrons, protons and neutrons, and vice versa. Dubverse video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Worked example: Identifying isotopes and ions Let's figure out how to identify isotopes and ions from the number of electrons, protons and neutrons, and vice versa. https://cdn.kastatic.org/ka-youtube-converted/RlegO58V8Bg.mp4/RlegO58V8Bg.mp4 224 Structure of Atom https://www.khanacademy.org/science/class-9-chemistry/x46dd29ce84a663ea:structure-of-the-atom/x46dd29ce84a663ea:atomic-number-mass-number-isotopes-and-isobars/v/isobars 2023-06-26T12:36:08.867767149Z Isobars We've seen atoms of same elements with same atomic number but different atomic masses, but now, let's have a look at atoms of different elements with same atomic mass! Vibhor Pandey video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Isobars We've seen atoms of same elements with same atomic number but different atomic masses, but now, let's have a look at atoms of different elements with same atomic mass! https://cdn.kastatic.org/ka-youtube-converted/9xwmJ_aI-6o.mp4/9xwmJ_aI-6o.mp4 149 Structure of Atom https://www.khanacademy.org/science/mh-grade-8-science/x0f256b8de9c7cf34:inside-the-atom/x0f256b8de9c7cf34:atomic-number-and-mass-number/e/lo-2-3-atomic-number-and-mass-number 2025-08-05T18:56:35.058002345Z Atomic number and mass number Let's solve some problems to better understand atomic and mass numbers. Aakash Bagga exercise https://www.khanacademy.org/science/mh-grade-8-science/x0f256b8de9c7cf34:inside-the-atom/x0f256b8de9c7cf34:atomic-number-and-mass-number/e/isotopes-and-formation-of-ions 2026-04-07T23:55:07.30621384Z Isotopes, formation of ions and valency Let's solve some questions Vibhor exercise https://www.khanacademy.org/science/class-9-chemistry/x46dd29ce84a663ea:structure-of-the-atom/x46dd29ce84a663ea:atomic-number-mass-number-isotopes-and-isobars/e/isotopes-and-isobars 2026-04-08T08:09:55.69362548Z Isotopes and Isobars Let's solve a few problems to understand the concept of isotopes and isobars. Aanchal Arora exercise https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:atoms-isotopes-and-ions/x2613d8165d88df5e:ions/e/apply-ions 2026-01-23T20:40:31.40044183Z Apply: ions Apply your understanding of ions in this set of free practice questions. Megan Cohn exercise