https://www.khanacademy.org/science/hs-integrated-physics-chemistry-tx/xffee0b339ed6ea67:the-periodic-table 2026-06-30T16:40:46.52584181Z The periodic table Explore and uncover the hidden patterns within the periodic table of elements. Learn how the table is structured to allow us to make predictions about the physical and chemical properties of every known element. Uncover how to use Lewis diagrams to represent valence electrons in atoms and ions. unit