https://www.khanacademy.org/science/chemistry/atomic-structure-and-properties/copy-of-periodic-table-of-elements/v/periodic-table-groups 2022-09-07T08:21:01.673602243Z Groups of the periodic table The s-, p-, and d-block elements of the periodic table are arranged into 18 numbered columns, or groups. The elements in each group have the same number of valence electrons. As a result, elements in the same group often display similar properties and reactivity. Sal Khan video https://cdn.kastatic.org/ka_thumbnails_cache/bf6fd19a-167e-41d3-a67f-7032ecf1249b_1280_720_base.png Groups of the periodic table The s-, p-, and d-block elements of the periodic table are arranged into 18 numbered columns, or groups. The elements in each group have the same number of valence electrons. As a result, elements in the same group often display similar properties and reactivity. https://cdn.kastatic.org/ka-youtube-converted/jQGUkJc7_04.mp4/jQGUkJc7_04.mp4 461 Periodic table and electron configurations https://www.khanacademy.org/science/strengthened-shs-chemistry-1/x174677b2bfa4bea2:1st-quarter/x174677b2bfa4bea2:periodic-table-and-electron-configurations/e/groups-and-periods--find-the-atomic-number 2021-04-29T07:53:56Z Groups and periods: find the atomic number Let's practice on finding the atomic number of an element by knowing its group and period number. Chaitra exercise