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Science

Transition Metals

Overview

Students explore the chemistry of the transition elements — the central block of the periodic table — discovering the features that make them uniquely useful in industry, biology, and technology.

Learning Objective
Students understand the distinctive properties of transition metals and can explain why they act as catalysts and form coloured compounds.

Resources needed

  • None — or iron, copper, and any available coloured transition metal compound

Lesson stages

0 / 7 done
  1. 1 Ask: what do iron, copper, titanium, and chromium have in common? (All are transition metals, used extensively in industry and biology).
  2. 2 Introduce transition metals: elements in the d-block of the periodic table (Groups 3-12). They include iron, copper, nickel, zinc, titanium, chromium, and others.
  3. 3 Property 1 — variable oxidation states: iron exists as Fe2+ and Fe3+; copper as Cu+ and Cu2+. This is because d-electrons can be lost in different numbers.
  4. 4 Property 2 — coloured compounds: transition metal ions absorb specific wavelengths of visible light, giving them colour. Iron(III) is red/orange, copper(II) is blue, cobalt(II) is pink.
  5. 5 Property 3 — catalytic activity: transition metals and their compounds are widely used as catalysts. Iron in the Haber process (making ammonia), vanadium pentoxide in making sulfuric acid, platinum in catalytic converters.
  6. 6 Biological example: iron in haemoglobin (carries oxygen), cobalt in vitamin B12, zinc in many enzymes.
  7. 7 Ask: why do transition metals make good catalysts? (Variable oxidation states allow them to gain and lose electrons easily, facilitating electron transfer in reactions).

Tap a step to mark it as done.

Variations

  • Test the colour of different transition metal solutions.
  • Research the catalytic converter: how does platinum, palladium, and rhodium convert toxic exhaust gases to less harmful ones?
  • Discuss iron in haemoglobin: how does the iron ion bind oxygen? What happens in carbon monoxide poisoning?
More information

Teach: transition metal, d-block, oxidation state, catalyst, complex ion, ligand, haemoglobin. The three key properties — variable oxidation states, coloured compounds, catalytic activity — all arise from the partially filled d electron subshell.

Focus on the three properties and one example of each before introducing the biological and industrial applications.

Can students name three properties of transition metals and explain one of them in terms of electron structure? Can they give an industrial and a biological example of transition metal catalysis?

Copper sulfate solution (blue) and any iron salt (orange/brown) demonstrate coloured transition metal compounds very cheaply. No other specialist materials needed.

Students sometimes think all metals in the centre of the periodic table are transition metals. Define transition metals specifically as elements with a partially filled d subshell in at least one common oxidation state — zinc and scandium are borderline cases.

Transition metals are central to industrial chemistry, technology, and biology. From the iron in our blood to the titanium in aircraft to the platinum in fuel cells, their unique electronic properties make them indispensable.