https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:atomic-structure-and-properties/x2eef969c74e0d802:periodic-trends/v/atomic-and-ionic-radii 2021-01-04T18:35:18Z Atomic and ionic radii Atomic and ionic radii are found by measuring the distances between atoms and ions in chemical compounds. On the periodic table, atomic radius generally decreases as you move from left to right across a period (due to increasing nuclear charge) and increases as you move down a group (due to the increasing number of electron shells). Similar trends are observed for ionic radius, although cations and anions need to be considered separately. Jay video https://cdn.kastatic.org/googleusercontent/OtLCosmSgkrprxD8aa4wAgHHnV9yR8ALfEAbwQdK7VHWSabodfCPHuwxsP86c4KCwvHfMzvUnzjEIaidEYOz31xo7Q Atomic and ionic radii Atomic and ionic radii are found by measuring the distances between atoms and ions in chemical compounds. On the periodic table, atomic radius generally decreases as you move from left to right across a period (due to increasing nuclear charge) and increases as you move down a group (due to the increasing number of electron shells). Similar trends are observed for ionic radius, although cations and anions need to be considered separately. https://cdn.kastatic.org/ka-youtube-converted/rKoIcgBM4Vg.mp4/rKoIcgBM4Vg.mp4 686 Atomic and Ionic Radii https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:atomic-models-and-periodicity/x2613d8165d88df5e:periodic-trends/v/atomic-radii-trends 2023-12-15T18:39:28.793791463Z Atomic radii trends Atoms are not all the same size. The relative size of the atoms follows a set of trends on the periodic table. Going across a period, the main group elements tend to decrease in atomic radius due to the increased nuclear charge. Going down a group, the main group elements tend to increase in atomic radius due to increased shielding and the addition of new shells to the structure of the atom. Sal Khan video https://cdn.kastatic.org/ka_thumbnails_cache/b20fde22-88b0-4dfa-8d69-9a73f51373fa_1280_720_base.png Atomic radii trends Atoms are not all the same size. The relative size of the atoms follows a set of trends on the periodic table. Going across a period, the main group elements tend to decrease in atomic radius due to the increased nuclear charge. Going down a group, the main group elements tend to increase in atomic radius due to increased shielding and the addition of new shells to the structure of the atom. https://cdn.kastatic.org/ka-youtube-converted/RrwL99bEotk.mp4/RrwL99bEotk.mp4 288 Atomic and Ionic Radii https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:atomic-models-and-periodicity/x2613d8165d88df5e:periodic-trends/e/apply-atomic-radii-trends 2026-03-11T05:00:37.141016324Z Apply: atomic radii trends Apply your understanding of atomic radii trends in this set of free practice questions. Eric exercise