140 likes | 261 Views
Unless otherwise stated, all images in this file have been reproduced from: Blackman, Bottle, Schmid, Mocerino and Wille, Chemistry , 2007 (John Wiley) ISBN: 9 78047081 0866 . CHEM1002 [Part 2]. Dr Michela Simone Lecturer BSc (I Hons ), MSc , D.Phil. (Oxon), MRSC, MRACI
E N D
Unless otherwise stated, all images in this file have been reproduced from: Blackman, Bottle, Schmid, Mocerino and Wille,Chemistry, 2007 (John Wiley) ISBN: 9 78047081 0866
CHEM1002 [Part 2] Dr Michela Simone Lecturer BSc (I Hons), MSc, D.Phil. (Oxon), MRSC, MRACI Weeks 8 – 13 Office Hours: Monday 3-5, Friday 4-5 Room: 412A (or 416) Phone: 93512830 e-mail:michela.simone@sydney.edu.au
Summary of Last Lecture • Complexes II • For octahedral complexes with formulae [MX2Y4], cis and trans geometrical isomers are possible • For square planar complexes with formulae [MX2Y2], cis and trans geometrical isomers are possible • For octahedral complexes with bidentateligands, optical isomerism is also possible • Metal complex formation can greatly increase solubility
Complexes III • Lecture 14 • Transition Metals • Electron Configuration • Oxidation States • Colours • Magnetism • Blackman Chapter 13, Sections 13.4 and 13.7 • Lecture 15 • Metals in Biological Processes • Essential Elements • Toxic Elements • Medicinal Uses • Blackman Chapter 13
Electronic Configurations of Atoms • In 4th row, 4s and 3dorbitals are available for electrons • There is one 4s orbital: it can accommodate 2 electrons • There are five 3dorbitals: each can accommodate 2 electrons, giving a total of 10 electrons • Fill 4s then 3d energy 3d 4s
Atomic Configurations • Fill 4s then 3d • Group number gives number of valence electrons • Electronic configurations: • K: group 1 so [Ar](4s)1(3d)0 • Sc: group 3 so [Ar](4s)2(3d)1 • Mn: group 7 so [Ar](4s)2(3d)5 • Ni: group 10 so [Ar](4s)2(3d)8 • Zn: group 12 so [Ar](4s)2(3d)10 where x + y = group [Ar](4s)x(3d)y
Electronic Configurations of Cations • Fill 3d only • Group number gives number of valence electrons • Cation has (group number – oxidation number) electrons • Mn7+: group 7 and oxidation number 7 so has: • (7 – 7) = 0 electrons: [Ar](3d)0 • Mn2+: group 7 and oxidation number 2 so has • (7 – 2) = 5 electrons: [Ar](3d)5 • Ni2+: group 10 and oxidation number 2 so has • (10 – 2) = 8 electrons: [Ar](3d)8 • Ni3+: group 10 and oxidation number 3 so has • (10 – 3) = 7 electrons: [Ar](3d)7 (4s always empty!)
Electronic Configurations of Cations • To minimize repulsion between electrons, they occupy d-orbitalssingly with parallel spins until they have to pair up: • Mn2+: [Ar](3d)5 3d • Ni2+: [Ar](3d)8 3d • If the metal cation has unpaired electrons, the complex will be attracted to a magnet: paramagnetic
Aqueous Oxoanions of Transition Metals • One of the most characteristic chemical properties of these elements is the occurrence of multiple oxidation numbers, often associated with different colours. Ion Ox. No. Colour VO3-+5 yellow VO2+ +4 green V3+ +3 blue V2++2 violet
Colourful Complexes • Aqueous solutions of the Co(III) complexes (from left to right): [Co(NH3)5OH2]3+, [Co(NH3)6]3+, trans-[Co(en)2Cl2]+, [Co(en)2O2CO]+ and [Co(NH3)5Cl]2+. • All contain Co(III): colour influenced by the ligand
Absorbed and Observed Colours Unless the d-orbitals are empty, half full or full, electrons can be excited from one d-orbital to another: absorption of light which we see as colour
Summary: Complexes II • Learning Outcomes - you should now be able to: • Complete the worksheet • Work out the electron configurations of atoms and cations • Work out the number of unpaired electrons • Answer review problems 13.59-13.62 in Blackman • Next lecture: • The Biological Periodic Table