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Unit 18

Transition metals

Steel, copper wire, titanium alloys, catalysts and pigments — the modern world is built of transition metals. This unit explains why they have so many oxidation states and colours, how they are won from their ores, why they make good catalysts, visits the lanthanides, the actinides and the man-made superheavy elements, and ends inside your own blood, where one iron ion carries oxygen. Colours are computed from absorption spectra, and every judgement about smelting and catalysis comes from thermodynamic data.

6 lessons ≈ 180 min 0 of 6 lessons complete

  1. 1 Trends across the d-block Why do chromium and copper break the filling rules? Why are zirconium and hafnium the same size? Why can manganese reach +7 while zinc stops at +2? Radii, melting points and oxidation states across the d-block, starting from electron configurations. 30 min
  2. 2 Oxidation states and colour Potassium permanganate is deep purple, copper sulfate pale blue, zinc salts colourless; shake a vanadate solution with zinc and it turns from yellow through green and blue to green again and finally violet. Where do the colours come from? 30 min
  3. 3 Extracting metals Gold can be picked out of river sand, iron must be smelted with coke in a blast furnace, and aluminium needs electrolysis. Thermodynamics decides the reducing agent; the energy bill decides the price. 30 min
  4. 4 Catalysts and materials Iron makes ammonia, vanadium makes sulfuric acid, and platinum, palladium and rhodium clean exhaust gas. Why are transition metals such good catalysts? Then see how ferromagnetism and alloying make metals more useful still. 30 min
  5. 5 The f-block and beyond Fifteen lanthanides with almost identical chemistry power strong magnets and phosphors; every actinide is radioactive, and the isotopes of uranium keep a record of the Earth’s age. Finally, a look at the end of the periodic table. 25 min
  6. 6 Metals in biology: how haemoglobin carries oxygen The Fe²⁺ of haem flips from high to low spin when it binds O₂; four cooperating haems make a sigmoid curve that is steepest right at tissue pressures. Then the Bohr effect, carbon monoxide poisoning, and how a pulse oximeter reads blood oxygen at two wavelengths. 35 min