Calculate the atomic packing factor of quartz, knowing that the number of Si atoms per cm3 is 2.66x1022 and that the atomic radii of Si and O are 0.038 and 0.117 nm.

Choose one or more: Draw the Lewis structure. Consider and draw alternate resonance structures. Calculate the molar mass of the compound. Leave out the lone pairs of electrons. Complete the octets of each atom (dublet for H). Determine the central atom, if possible. Determine the number of covalent bonds in the structure. Check the structure with electron bookkeeping   Question: Determine which of the following procedures are steps in drawing the resonance structures of pyridine and pyrazine. Check all that apply.

1. Draw the shapes of the various d orbitals and explain why they are split into two groups; 12g and eg in an octahedral field Draw a diagram to show how the d orbitals are split into groups with different energy in an octahedral field. Some electronic configurations may exist in both high spin and low spin arrangements in an octahedral field. Draw all of these cases, and suggest which metal ions and which ligands might give rise to each. Draw an energy level diagram to show the lifting of degeneracy of the 3d orbitals in a tetrahedral ligand field . Give the number of unpaired electrons in a strong and weak octahedral field for (a) Cr² (b) Co and (c) Fe. Calculate the CFSE and magnetic moment in each case

9. Describe and explain the Jahn teller effect in octahedral complexes of Cu² and Cr Define paramagnetism and diamagnetism. What is the difference between an inner orbital complex and an outer orbital complex? The complex [NiCN)4] is diamagnetic, but [NiCla] is paramagnetic and has two unpaired electrons, explain these observations and deduce the structures of the two complexes The complex ion [Co (NH3)6] is octahedral and diamagnetic, the complexion [CoF6] is also octahedral but paramagnetic. How does valence bond theory account for this observation? How does crystal field explain color of complexes?

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.

15. Describe clearly how crystal field theory explains satisfactorily the magnetic moment of transition metal complexes. Which complex has the larger crystal field splitting? Give reasons for your answer. (i) [Co(CN)6] or (ii) [Co(H2O)²+ or (iii) [Co(NH)6] or [Co(NH3)6] [Co(H_O)] [Rh(NH3)]* What relationship exist between A (the crystal field splitting) and the pairing energy (P) in determining whether a given complex will be high spin or low spin.

Part 1 See Periodic Table Draw the major resonance contributor for the skeletal arrangement CNNO 2 (arrangement a). Include all nonbonding electrons and all nonzero formal charges. The skeleton has been given to you. Н Ν HCNO SE F ·N—N; ☑ P Cl Br I

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