Chemical Bonding: Ionic and Covalent

60 lessons, pages 561–620.

  1. Why Do Atoms Bond? — Stability, lower energy and the noble gas electron arrangement
  2. Valence Electrons and the Octet Rule — Outer-shell electrons and the drive towards a full shell
  3. Metals, Non-metals and the Type of Bond — How the elements involved decide between transfer and sharing
  4. Three Kinds of Strong Chemical Bond — An overview of ionic, covalent and metallic bonding
  5. Electron Transfer: How Ions Form — Losing and gaining electrons to reach a full outer shell
  6. Positive Ions from Metal Atoms — Electron loss, cations and why metals form positive ions
  7. Negative Ions from Non-metal Atoms — Electron gain, anions and naming -ide ions
  8. Predicting Ion Charges from Group Number — Using the periodic table to work out the charge on an ion
  9. Dot-and-Cross Diagrams: The Conventions — Dots, crosses, brackets and charges in bonding diagrams
  10. Dot-and-Cross Diagram for Sodium Chloride — Showing one electron moving from sodium to chlorine
  11. Dot-and-Cross Diagram for Magnesium Oxide — Transferring two electrons to form 2+ and 2- ions
  12. Dot-and-Cross Diagram for Magnesium Chloride — When one metal atom gives electrons to two non-metal atoms
  13. Dot-and-Cross Diagrams for Sodium Oxide and Aluminium Oxide — Unequal ion ratios and balancing electrons lost and gained
  14. Writing Ionic Formulae by Balancing Charges — Why total positive charge equals total negative charge
  15. Compound Ions in Ionic Compounds — Sulfate, nitrate, carbonate, hydroxide and ammonium in formulae
  16. The Ionic Bond: Electrostatic Attraction — Strong forces between oppositely charged ions in all directions
  17. The Giant Ionic Lattice — Regular three-dimensional arrangements of ions in a crystal
  18. Ion Charge, Ion Size and Bond Strength — Why magnesium oxide holds together more strongly than sodium chloride
  19. High Melting Points of Ionic Compounds — The energy needed to overcome strong lattice attractions
  20. Ionic Compounds and Electrical Conductivity — Why ions must be free to move to carry charge
  21. Ionic Compounds Dissolving in Water — Water molecules surrounding and separating ions
  22. Why Ionic Crystals Are Brittle — Layers shifting until like charges repel
  23. Models of Ionic Structures and Their Limitations — Ball-and-stick, space-filling and 2D diagrams compared
  24. Ionic Bonding Checkpoint — Practising ion formation, diagrams, formulae and properties
  25. Electron Sharing: The Covalent Bond — Non-metal atoms sharing pairs of electrons
  26. Why a Shared Pair Holds Atoms Together — Attraction of both nuclei for the shared electrons
  27. Dot-and-Cross Diagram for Hydrogen — The simplest covalent bond in the H₂ molecule
  28. Dot-and-Cross Diagram for Chlorine — Single bonds in the halogen molecules
  29. Dot-and-Cross Diagram for Hydrogen Chloride — A single bond between two different atoms
  30. Dot-and-Cross Diagram for Water — Two bonding pairs and two lone pairs on oxygen
  31. Dot-and-Cross Diagram for Ammonia — Three bonding pairs and one lone pair on nitrogen
  32. Dot-and-Cross Diagram for Methane — Carbon forming four single covalent bonds
  33. How Many Bonds? Valency of Non-metals — Predicting the number of covalent bonds from group number
  34. Bonding Pairs and Lone Pairs — Identifying and counting electron pairs in a molecule
  35. Double Bonds: The Oxygen Molecule — Sharing two pairs of electrons in O₂
  36. Dot-and-Cross Diagram for Carbon Dioxide — Two double bonds around a central carbon atom
  37. Dot-and-Cross Diagram for Ethene — A carbon-carbon double bond in a hydrocarbon
  38. Triple Bonds: The Nitrogen Molecule — Three shared pairs and the stability of N₂
  39. Displayed Formulae and Other Ways to Show Molecules — Lines for bonds, molecular formulae and 3D models
  40. Bond Length and Bond Strength — How single, double and triple bonds compare
  41. Dative Covalent Bonds — When one atom supplies both shared electrons, as in NH₄⁺
  42. Simple Molecular Substances — Small molecules held together by strong covalent bonds
  43. Covalent Bonds versus Intermolecular Forces — Forces within molecules and forces between molecules
  44. Properties of Simple Molecular Substances — Low melting points and poor electrical conductivity
  45. Giant Covalent Structures: Diamond — Each carbon bonded to four others in a rigid network
  46. Giant Covalent Structures: Graphite — Layers, delocalised electrons and softness
  47. Giant Covalent Structures: Silicon Dioxide — The network structure of sand and quartz
  48. Comparing Simple Molecular and Giant Covalent Substances — Why both contain covalent bonds yet behave so differently
  49. Electronegativity: Unequal Sharing — How strongly an atom attracts a shared pair of electrons
  50. Polar Covalent Bonds — Partial charges on atoms in bonds such as H-Cl and O-H
  51. The Bonding Continuum from Ionic to Covalent — Electron transfer and sharing as two ends of a scale
  52. Metallic Bonding Compared with Ionic and Covalent — A sea of delocalised electrons around positive ions
  53. Identifying Bond Type from Properties — Using melting point, conductivity and solubility as evidence
  54. Predicting Bond Type from the Periodic Table — Metal with non-metal, non-metal with non-metal
  55. Dot-and-Cross Diagrams: Common Errors — Spotting and fixing mistakes in ionic and covalent diagrams
  56. Limitations of Simple Bonding Models — Where the octet rule and dot-and-cross diagrams fall short
  57. Bonding in Everyday Materials — Salt, water, plastics, sand and pencil lead explained
  58. Structure and Bonding Summary — Comparing ionic, simple molecular, giant covalent and metallic
  59. Exam Skills: Explaining Properties Using Bonding — Linking structure, forces and energy in written answers
  60. Chemical Bonding: Unit Review — Connecting electron transfer, electron sharing and dot-and-cross diagrams