I'm teaching A2 for the first time (eek!). My understanding of transition metals is that they can form an ion with a partially filled d-sublevel so there are d-d electron transitions and therefore a colour. This is the definition I have in a revision book and it makes sense. In the AQA spec it says that a transition metal is one with an atom <u>or</u> ion with an incomplete d-sublevel. Now, by this definition Sc is a transition metal, having 4s2 3d1 but it is not and AQA are giving the TMs as Ti-Cu. I'm obviously missing something here. How can the AQA definition stand unless Sc is counted as a TM?