Why Oxygen Is Magnetic: Molecular Orbitals | General Chemistry 1.9

Pour liquid nitrogen between the poles of a strong magnet and it falls straight through; pour liquid oxygen and it hangs there. A Lewis structure pairs every electron in oxygen, so it can't explain the pull. This episode builds molecular orbitals from overlapping atomic waves, from hydrogen and helium through the second row, including the s-p mixing that reorders the ladder for boron, carbon and nitrogen. Oxygen ends up with two unpaired electrons and a bond order of two, and the season closes with what happens when 10²³ atoms share their levels. Chapters 0:00 Liquid nitrogen and liquid oxygen at a magnet 1:19 Faraday and paramagnetism 1:44 Lewis's oxygen problem 2:17 Electron pairs pinned in place 2:32 Two waves overlap 3:16 Bonding and antibonding sigma orbitals 3:27 H₂, He₂ and bond order 4:47 The second row 5:15 2p orbitals head-on 5:32 2p orbitals side by side 5:50 Which is lower, sigma or pi? 6:49 s-p mixing reorders the ladder 8:09 Filling oxygen's ladder 9:09 Oxygen's bond order 9:43 Hund, Mulliken and Lennard-Jones 10:12 Fluorine and neon 10:31 Bond order, bond energy and bond length 11:11 Nitric oxide 11:30 Lewis structures and orbitals together 12:05 Back to the magnet 12:21 Three things to take away 12:51 Looking back on the season 13:04 From two atoms to a band Reference: Steven S. Zumdahl and Susan A. Zumdahl, *Chemistry*, 7th ed, sections 9.2-9.5. Historical sources: Faraday, Experimental Researches in Electricity, 25th series, Phil. Trans. 141, 7 (1851): https://jimclifford.ca/philosophical-... · Royal Society archive, Dewar to William Thomson (1891): https://catalogues.royalsociety.org/C... · Lewis, Valence and the Structure of Atoms and Molecules (1923): https://archive.org/download/valences... · Lennard-Jones, Trans. Faraday Soc. (1929), excerpt: https://chemteam.info/Chem-History/Le... · Nobel Prize in Chemistry 1966, Mulliken, lecture: https://www.nobelprize.org/uploads/20... Previous episode: 1.8 "The Shapes of Molecules". This is the season one finale. Narration: AI voice (ElevenLabs); music: AI-generated (Lyria) and original synthesized tracks.