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 Periodic properties 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 Periodic properties 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 https://www.khanacademy.org/science/grade-11-chemistry-snc-aligned/x203b0fc81a964b2d:periodic-table-and-periodic-properties/x203b0fc81a964b2d:periodic-properties/e/trends-in-physical-properties-of-alkali-metals 2023-01-08T23:01:04.257555066Z Trends in the physical properties of alkali metals Alkali metals show regular trends in their physical properties. Through this exercise, we will test our understanding of the various characteristics of alkali metals like atomic and ionic radii, ionisation enthalpy, hydration enthalpy and the anomalous behaviour of a particular alkali metal. Revathi exercise https://www.khanacademy.org/science/chemistry/atomic-structure-and-properties/periodic-table-trends-bonding/v/atomic-radius-trend 2021-01-04T18:35:18Z Atomic radius trends on periodic table How atomic radius is defined, and trends across a period and down a group. Sal Khan video https://cdn.kastatic.org/googleusercontent/wPur6xJb3jGMXgdi0bjIrXHKq9cxiKIFqPFNjDNTSUROzeO4CCnLmpfJZV8UdcOJHHdpexBf_zUmw826lyj_ub5T1g Atomic radius trends on periodic table How atomic radius is defined, and trends across a period and down a group. https://cdn.kastatic.org/ka-youtube-converted/q--2WP8wXtk.mp4/q--2WP8wXtk.mp4 580 Periodic properties https://www.khanacademy.org/science/grade-11-chemistry-snc-aligned/x203b0fc81a964b2d:periodic-table-and-periodic-properties/x203b0fc81a964b2d:periodic-properties/e/trend-in-the-atomic-size 2026-02-27T12:30:36.531197313Z Periodic trends of atomic size Let's practice to learn the periodic trends in the atomic size of elements in the modern periodic table. Let's solve some questions to check the trends when we move from left to right (across the period) and top to bottom (down the group) of the periodic table. Chaitra exercise https://www.khanacademy.org/science/chemistry/atomic-structure-and-properties/periodic-table-trends-bonding/v/ionization-energy-trends 2021-01-04T18:35:18Z Ionization energy trends Definition of ion and ionization energy, and trends in ionization energy across a period and down a group. video https://cdn.kastatic.org/googleusercontent/s0-9EWc11XiGfxIK8JZkVD-POI83d0jCkUXJBf4lBDHGs5GPC3l693YeJWDYzZpP3sGq_f7tw1izFiqiRjYDTjnD Ionization energy trends Definition of ion and ionization energy, and trends in ionization energy across a period and down a group. https://cdn.kastatic.org/ka-youtube-converted/5CBs36jtZxY.mp4/5CBs36jtZxY.mp4 602 Periodic properties https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:atomic-models-and-periodicity/x2613d8165d88df5e:periodic-trends/v/ionization-energy-trends-hs 2023-12-15T18:39:28.793791463Z Ionization energy trends Ionization is the process of removing an electron from a neutral atom (or compound). The energy required to remove an electron is the ionization energy. The ionization energy differs for each atom. There are trends that match the structure of the periodic table. Across a period, ionization energy tends to increase. Down a group, the ionization energy tends to decrease. Sal Khan video https://cdn.kastatic.org/ka_thumbnails_cache/44ba4dcb-7ee8-4816-ae19-d37081115519_1280_720_base.png Ionization energy trends Ionization is the process of removing an electron from a neutral atom (or compound). The energy required to remove an electron is the ionization energy. The ionization energy differs for each atom. There are trends that match the structure of the periodic table. Across a period, ionization energy tends to increase. Down a group, the ionization energy tends to decrease. https://cdn.kastatic.org/ka-youtube-converted/MyBYZJ3Wo_0.mp4/MyBYZJ3Wo_0.mp4 272 Periodic properties https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:atomic-structure-and-properties/x2eef969c74e0d802:periodic-trends/v/group-trend-for-ionization-energy 2020-08-28T01:50:07Z Ionization energy: group trend An element's first ionization energy is the energy required to remove the outermost, or least bound, electron from a neutral atom of the element. On the periodic table, first ionization energy generally decreases as you move down a group. This is because the outermost electron is, on average, farther from the nucleus, meaning it is held less tightly and requires less energy to remove. Jay video https://cdn.kastatic.org/googleusercontent/2LyY-rZJgaHqGfQ2logedUkcFo-cinTMJQXeddxMk3glTPzlOWhoYuxds0LU_0W14kE2sbFCY_rW-td5nfJo25TU Ionization energy: group trend An element's first ionization energy is the energy required to remove the outermost, or least bound, electron from a neutral atom of the element. On the periodic table, first ionization energy generally decreases as you move down a group. This is because the outermost electron is, on average, farther from the nucleus, meaning it is held less tightly and requires less energy to remove. https://cdn.kastatic.org/ka-youtube-converted/vQLcxlvK7Ik.mp4/vQLcxlvK7Ik.mp4 619 Periodic properties https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:atomic-structure-and-properties/x2eef969c74e0d802:periodic-trends/v/period-trend-for-ionization-energy 2022-10-05T02:43:18.611402953Z Ionization energy: period trend An element's first ionization energy is the energy required to remove the outermost, or least bound, electron from a neutral atom of the element. On the periodic table, first ionization energy generally increases as you move left to right across a period. This is due to increasing nuclear charge, which results in the outermost electron being more strongly bound to the nucleus. Jay video https://cdn.kastatic.org/googleusercontent/RGU--PmvCcmX-TmlEkKj_e2HNVx53urks3b1d7pG7nG94xFBavjxe2BNA0nWqS5351bAhex0UgdVqIybRQAPq2eFgg Ionization energy: period trend An element's first ionization energy is the energy required to remove the outermost, or least bound, electron from a neutral atom of the element. On the periodic table, first ionization energy generally increases as you move left to right across a period. This is due to increasing nuclear charge, which results in the outermost electron being more strongly bound to the nucleus. https://cdn.kastatic.org/ka-youtube-converted/649ZlWMp0LE.mp4/649ZlWMp0LE.mp4 603 Periodic properties https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:atomic-structure-and-properties/x2eef969c74e0d802:periodic-trends/v/worked-example-identifying-element-from-successive-ionization-energies 2022-10-05T02:43:18.611402953Z Worked example: Identifying an element from successive ionization energies When electrons are removed in succession from an element, the transition from removing valence electrons to removing core electrons results in a large jump in ionization energy. By looking for this large jump in energy, we can determine how many valence electrons an element has, which in turn can help us identify the element. Sal Khan video https://cdn.kastatic.org/ka_thumbnails_cache/28c4e907-e8e0-46f5-b91e-872e39dd6c96_1280_720_base.png Worked example: Identifying an element from successive ionization energies When electrons are removed in succession from an element, the transition from removing valence electrons to removing core electrons results in a large jump in ionization energy. By looking for this large jump in energy, we can determine how many valence electrons an element has, which in turn can help us identify the element. https://cdn.kastatic.org/ka-youtube-converted/PfL-gzDdOBo.mp4/PfL-gzDdOBo.mp4 151 Periodic properties https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:atomic-structure-and-properties/x2eef969c74e0d802:periodic-trends/v/first-and-second-ionization-energy 2021-01-04T18:35:19Z First and second ionization energy An element's second ionization energy is the energy required to remove the outermost, or least bound, electron from a 1+ ion of the element. Because positive charge binds electrons more strongly, the second ionization energy of an element is always higher than the first. Jay video https://cdn.kastatic.org/googleusercontent/mG8k0I_tGaYGJlGfdFJugbFRHGAPLQQYjhoh1OupCa8kS4kXq9nwbzhJeBmx54Bm-Ywa6xCizAGHEPojkCvcu7fX First and second ionization energy An element's second ionization energy is the energy required to remove the outermost, or least bound, electron from a 1+ ion of the element. Because positive charge binds electrons more strongly, the second ionization energy of an element is always higher than the first. https://cdn.kastatic.org/ka-youtube-converted/uVWquWFjnCw.mp4/uVWquWFjnCw.mp4 455 Periodic properties https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:atomic-models-and-periodicity/x2613d8165d88df5e:periodic-trends/e/apply-ionization-energy-trends 2026-03-11T05:00:37.141016324Z Apply: ionization energy trends Apply your understanding of ionization energy trends in this set of free practice questions. Eric exercise