Episode 7 of the "Shedding Light on Atoms" series explains how the atoms of non-metals bond together with covalent bonds to form molecules. Science teacher Spiro Liacos introduces the concepts of electron dot diagrams, structural formulas, electron configuration, and organic chemistry.

Originally released by Liacos Educational Media, 2015. Streaming video file encoded with permission for digital streaming by Infobase on February 17, 2016. Link to website with Teacher's notes and Question Sheet for students available under Additional info tag.

Compounds and Molecules --(2:11) -- How Do Atoms Bond? -- (1:40) -- Covalent Bonds -- (3:05) -- Stable Arrangements of Molecules -- (3:07) -- Valence Shells -- (1:50) -- Electron Dot Diagram -- (2:29) -- Ionic Bonds and Alloys -- (2:12) -- Single, Double, and Triple Bonds -- (2:38) -- History of Valency -- (4:56) -- Structural Diagram -- (1:41) -- Arrangement of Bonds -- (2:22) -- Chemical Formulas -- (4:20) -- Structural Formulas -- (2:40) -- Credits: Covalent Bonding: Shedding Light on Atoms, Episode 7 -- (0:28). Contents: Part A: Introduction: CH4 exists, but there’s no such thing as CH3, or CH2, or CH. Why is this? Why do atoms join together only in certain fixed ratios? Well, it has a lot to do with their electron configurations. Part B: My name is Bond, Covalent Bond: Covalent bonds form when pairs of electrons are mutually attracted by the nuclei of two different atoms. It’s often described as a sharing of electrons between two different atoms, but it’s really more like a tug-of-war. Atoms continue to bond with other atoms until their outer shells are full. “Electron dot diagrams” are used to represent molecules and the electron distribution within them. Part C: Single, Double, and Triple Bonds: Quite often, atoms can be held together with not just one shared pair of electrons, but with two and three shared pairs of electrons. Part D: Valency: Atoms can form only a fixed number of bonds. The number is called the atom’s valency. Structural formulas allow us to represent molecules more easily than with electron dot diagrams. Part E: Working Out Structural Formulas: The study of “Organic Chemistry” (the study of compounds containing carbon atoms) allowed scientists in the mid-1800s to work out the formulas and structures of quite a few molecules. They even developed the idea of double and triple bonds some 50 years before electrons were even discovered!.