CIE Nov 2014 v3 Paper 4 Q3

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PMT Transition elements have characteristic properties due to their partially- lled d orbitals. (a) (i) Which two elements in therst row of the d-block have only one electron in the 4s orbital of their neutral atoms?(ii) The d orbitals in an isolated transition metal atom or ion are described as being degenerate. What is meant by the term degenerate?(iii) Sketches of the shapes of the atomic orbitals from the d subshell are shown. In an octahedral complex, the d orbitals are split into two groups at different energy levels. On the diagram below, write an H in the box under each of the orbitals at the higher energy level. [4]UCLES 2014 9701/43/O/N/14 [Turn over<br /> PMT (b) The following scheme shows some reactions of Cu2+(aq). a few drops of NH3(aq) Cu2+(aq) pale blue precipitate A concentrated HCl excess NH3(aq) solution of C solution of B heat with Cu(s) [CuCl 2](aq) (i) Suggest the formula of each of the following. ABC(ii) State the colour of the following solutions. solution of Bsolution of C(iii) Name the type of reaction that occurs when C is heated with copper.Deduce the role of the copper metal in this reaction.[6] (c) When the solution containing the complex [CuCl 2] is poured into water, a precipitate of CuCl is formed. CuCl is white because it does not absorb visible light. Explain why CuCl does not absorb visible light.[2]UCLES 2014 9701/43/O/N/14<br /> (d) The complex ion [Cr(H2O)6]3+ is coloured because it absorbs visible light. The absorption spectrum for [Cr(H2O)6]3+ is shown below. PMT absorbance 400 violet 500 wavelength / nm 600 red Suggest the colour of this complex ion. Explain your answer.[2] [Total: 14]UCLES 2014 9701/43/O/N/14 [Turn over<br />

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