5. Show how the d orbital splitting changes as an octahedral complex undergoes tetragonal distortion and eventually becomes a square planar complex. What is the spectrochemical series and what is its importance Using crystal field theory, (a) Draw the d-orbital electronic configuration of [Cr(CN)6]³ (b) How many unpaired electrons are present? (c) Calculate the CFSE and magnetic moment of the complex ion (c) If six Br groups were substituted for the six CN groups to give [CrBr.]³ would you expect Ao to increase or decrease? Why? Describe how Ao changes as the charge on the metal changes from M² to M and how it changes between a first row, second row or third row transition element.

Part 1 See Periodic Table One resonance structure of CNO¯ is shown. In the first box, add two curved arrows to show the movement of electrons that result in the resonance form with a -1 formal charge on the oxygen atom. In the second box, draw this resonance form with the -1 formal charge on the oxygen atom by adding bonds, lone pairs, and non-zero formal charges. =0% → [N=C=O 1 N-C-0

Draw any major resonance contributor for S2O3, assuming that the S atoms are bonded to each other, and the O atoms are bonded to S atoms. Include all nonbonding electrons and all nonzero formal charges.