The Periodic Table: Basics

50 lessons, pages 511–560.

  1. Why Chemists Need a Periodic Table — Organising more than a hundred elements so patterns become visible
  2. Early Attempts to Classify Elements — Döbereiner's triads and Newlands' law of octaves
  3. Mendeleev's Periodic Table — Ordering by atomic mass, leaving gaps and predicting new elements
  4. From Atomic Mass to Atomic Number — Moseley's work and why proton number fixes an element's place
  5. Reading the Modern Periodic Table — Symbols, atomic numbers and relative atomic masses in each box
  6. Periods: The Horizontal Rows — Seven periods and what moving along a row means
  7. Groups: The Vertical Columns — Group numbering and families of similar elements
  8. Locating an Element by Group and Period — Using coordinates on the table to find and describe elements
  9. Blocks of the Periodic Table — An introduction to the s-, p-, d- and f-blocks
  10. Main-Group Elements and Transition Elements — The central block and how it differs from the outer groups
  11. The Lanthanides and Actinides — Why two rows sit below the main table
  12. Hydrogen: An Element Without a Fixed Home — Why hydrogen resembles both Group 1 and Group 7
  13. Electron Shells and the Periodic Table — How the number of occupied shells matches the period number
  14. Electron Arrangements of the First Twenty Elements — Writing arrangements such as 2,8,1 from atomic number
  15. Valence Electrons: The Outer Shell — Defining valence electrons and why they control chemistry
  16. Group Number and Valence Electrons — Linking main-group number to outer-shell electron count
  17. Why Elements in a Group Behave Alike — Same outer-shell arrangement, similar reactions
  18. Stable Outer Shells and the Noble Gases — Full outer shells and chemical unreactivity
  19. Gaining and Losing Electrons to Form Ions — How valence electrons predict common ion charges
  20. Valency and Combining Power — Using position in the table to predict simple formulae
  21. Metals and Non-metals on the Periodic Table — The staircase line dividing the two broad classes
  22. Physical Properties of Metals — Lustre, conductivity, malleability, ductility and high density
  23. Physical Properties of Non-metals — Dull, brittle, insulating and often low melting
  24. Chemical Behaviour of Metals and Non-metals — Electron loss versus electron gain and the oxides they form
  25. Acidic and Basic Oxides — Metal oxides as bases and non-metal oxides as acids
  26. Metalloids: Elements on the Borderline — Silicon, germanium and their in-between properties
  27. Exceptions to the Metal and Non-metal Rules — Mercury, graphite, iodine and other surprising cases
  28. Metallic Character Across a Period — From reactive metals on the left to non-metals on the right
  29. Metallic Character Down a Group — Why elements become more metallic lower in a group
  30. Group 1: The Alkali Metals — Soft, low-density metals with one valence electron
  31. Alkali Metals and Water — Forming hydroxides and hydrogen, and the reactivity trend down the group
  32. Why Alkali Metals Get More Reactive Down the Group — Outer electron distance, shielding and ease of loss
  33. Group 2: The Alkaline Earth Metals — Two valence electrons and a gentler reactivity pattern
  34. Group 7: The Halogens — Diatomic non-metals with seven valence electrons
  35. Trends in the Halogens — Colour, state and melting point changes down the group
  36. Halogen Displacement Reactions — A more reactive halogen displacing a less reactive one from a salt
  37. Why Halogens Get Less Reactive Down the Group — Attracting an extra electron into a more distant shell
  38. Group 0: The Noble Gases — Monatomic gases, their properties and everyday uses
  39. Trends in the Noble Gases — Boiling point and density rising down the group
  40. The Transition Metals — Hard, dense metals with coloured compounds and variable ions
  41. Transition Metals as Catalysts — Iron, nickel and platinum speeding up important reactions
  42. Comparing Group 1 Metals and Transition Metals — Melting point, density, hardness and reactivity side by side
  43. Elements of Period 3 — Sodium to argon: a tour across one complete row
  44. Predicting Properties from Position — Using group and period to forecast an unfamiliar element
  45. Predicting Unknown Elements: Mendeleev's Successes — Eka-silicon and germanium as a test of the periodic law
  46. Elements Beyond Uranium — Synthetic elements and how the table keeps growing
  47. The Periodic Table in Everyday Life — Elements in phones, lamps, medicines and materials
  48. Using the Interactive Periodic Table — Exploring categories and electron arrangements with the simulation
  49. Solving Periodic Table Problems — Multi-step questions linking position, electrons and properties
  50. The Periodic Table: Unit Review — Groups and periods, metals and non-metals, and valence electrons together