Transition elements

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In an advanced level course you only have to study the first-row d-block elements from scandium to zinc. You will discover that chemists make subtle distinctions so they typically exclude scandium and zinc and only regard the other eight elements as transition elements.
 
Transition elements are characterised by:

their electron configurations,

their physical properties,

their variable oxidation states,

the colour of many of their compounds,

the tendency for the metal ions to form complexes,

the catalytic activity of the metals and their compounds.

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Webguides

• Chemistry of complex ions
• A guide to transition metal chemistry
• Catalysis and transition metals

Recently Asked Questions

• I am using a colorimetric method to determine the mass of copper present in 1p coins. Firstly, to construct a calibration graph, how do you work out the concentrations needed to be put on the x-axis? For example, if 2 cm³of copper solution is put in a cuvette along with 3 cm³ deionised water, what would be the concentration of copper? Also, how are unknown determinations made in colorimetric analysis? Before the coin solution is put in the cuvette, would it have to be made up in a volumetric flask first or would I just put the dissolved coin straight in without water? 180309
• What is the purple intermediate formed when sodium thiosulphate and iron(III) chloride are added together? 180309
• I'm having trouble identifying the correct chemical equations for iodometric titration of copper and its resulting colour effects on the titration and end point. I don't know whether thiosulfate is titrating molecular iodine, or tri-iodide ions 2Cu²⁺ + 4I^- -> 2CuI(s) + I₂ I₂+2S₂O₃^2- -> 2I^- + S₄O₆^2- OR 2Cu²⁺ + 5I^- -> 2CuI(s) + I₃^- I₃^- + 2S₂O₃^2- -> 3I^- + S₄O₃^2- I realize that there is an equilibrium between I₃^- and I₂ in solution in the presence of I^-, however how can I determine which species is actually being titrated? Also, using the second set of equations, and accounting for the sodium balance in solution from adding the thiosulfate salt, I run into problems... 2NaS₂O₃ + I₃^- -> Na₂S₄O₃ + 2NaI However, the iodine now isn't balanced. Is there extra I^- in solution? And, if so, how does this impact the I₂ <=> I₃^- balance? Moreover, when extreme excess amounts of iodide are added to solution, the sample at first turns opaque brown (I'm guessing due to the precipitation of insoluble white copper iodide forming a suspension), but as the excess KI in solution dissolves, the sample turns translucent. What happened to the insoluble copper iodide, and why has the solution turned translucent brown? This is relevant to me because depending on the amount of KI added to solution before titration with thiosulfate, the end-point determinations change between a white end-point, or a clear end-point. 220209

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Tests

• Transition elements (A2)

updated: 14 September 2003