chapter 24 transition metals & coordination compounds
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Chapter 24 Transition Metals & Coordination Compounds. 24.2 Properties of Transition Metals Review Electron Configuration Trends in the Periodic Table 24.3 Coordination Compounds The Basics Example of Naming 24.4 Structure and Isomerization. - PowerPoint PPT PresentationTRANSCRIPT
Transition Metals & Coordination Compounds
Chapter 24Transition Metals &Coordination Compounds24.2 Properties of Transition MetalsReview Electron ConfigurationTrends in the Periodic Table24.3 Coordination Compounds The BasicsExample of Naming24.4 Structure and Isomerization
Transition Metals contain e- in d Orbitals
http://www.can-do.com/uci/lessons98/Periodic.htmlhttp://www.can-do.com/uci/lessons98/Periodic.htmlBreath slow down!2Why Are Transition Metals & Coordination Compounds Important?Therapeutic drugsChemical SensorsColoring agents PaintsCosmeticsBiological MoleculesHemeglobinChlorophyllGems (Jewelry & Technological Applications)Rubies, Emeralds, Garnets, etc.Lasers
24.2 Properties of Transition MetalsModerate to High DensitiesGood Electrical ConductivityHigh Melting PointsModerate to Extreme Hardness
http://www.tutorvista.com/chemistry/shapes-of-d-orbitalsDue to the delocalization of d electrons in metallic bondingExceptions: Elements with filled d orbitals, which prevents d-d bonding. Hg has a low melting point and is liquid at room temperature.
Electron Configuration
Increasing Energy(n-1)d(n-2)fElectron Configuration
[noble gas] ns2 (n-1)dx
[noble gas] ns2 (n-2)f14 (n-1)dx Slow down - Breath6Electron Configuration
[Kr]5s24d2http://malaxoschemistry.wikispaces.com/Periodic+TableAtomic Size
Decreasing SizeIncreasIng
S izehttp://malaxoschemistry.wikispaces.com/Periodic+TableAtomic Size
Exception to the trend: Electrons in the f-orbitals are not effective at shielding outer shell electrons from nuclear charge. So, the outer electrons are held in close this is known as lanthanide contraction.Keep it simple! breath9Ionization Energy
IncreasesDecreaseshttp://malaxoschemistry.wikispaces.com/Periodic+Table
Ionization EnergyException to the trend: Note that 5d elements have a greater ionization energy. This is again due to outer shell electron being held closer to the nucleus, so it take more energy to pull them away. Electronegativity
http://malaxoschemistry.wikispaces.com/Periodic+TableIncreasesDecreases
ElectronegativityException to the trend: There is an increase in electronegativity from the 3d (1st row transition metals) to the 4d (2nd row transition metals). Au: EN = 2.4Compared to P: EN = 2.1 !!Gold breath slow down13Oxidation States
In general, stability is found in full or half-full shells, and in a configuration that looks like a noble gas.Scandium1424.3 Coordination CompoundsComplex Ion - Central Metal bound to one or more ligandsLigands are Lewis Base* (electron donors) and can be either neutral or negatively chargedThe charge on the complex ion is balance by counter ions of opposite charge
The combination of a complex ion and counter ions results in a coordination compoundDavid N. Blauch - http://www.chm.davidson.edu/vce/index.htm
*Corrected 4/15/11 @ 2:30 pm)A Little BackgroundIn 1893, Swiss chemist Alfred Werner came up with the idea that a central metal could have 2 types of interactionsPrimary Valence Oxidation State of the central metalSecondary Valence Number of molecules or ions directly attached to the central metal or Coordination Number
Example: [Co(NH3)6]Cl3The Primary Valence or Oxidation State of Co is +3The Secondary Valence or Coordination Number is 6 (6 ammonia ligands are directly attached to Co
Other cobalt(III) coordination compounds[Co(NH3)6]Cl3[Co(NH3)5Cl]Cl2[Co(NH3)4Cl2]ClCoordinate Covalent BondsLewis Acid-Base Adduct the ligand donates its electrons to the empty metal orbitals to form a coordinate covalent bond
Lewis AcidLewis BaseML:AdductSome Common Ligands
Chelating AgentsLigands can have one or more bonding pairs of electronsMonodentateBidentate or Polydentate
Complex ions with bidentate or polydentate ligands are chelates, and the coordinating ligands are chelating agents
EDTA is hexadentatehttp://library.kiwix.org:4201/A/Inorganic_chemistry.htm
CoGeometries
Anne Marie Helmenstine, Ph.D., About.com Guide
Naming Coordination Compounds[Mn(CO)(NH3)5]SO4 (neutral ligands are written before charged ligands in the formula)Cation 1stName the ligands in alphabetical orderamminecarbonylAdd a prefix to indicate the number of ligandspentaammineName the metal ion Manganese(II)Anion 2ndSulfatePentaamminecarbonylmanganese(II) sulfate24.4 Structure & IsomerismSame formula different structuresDifferent connectivitiesSame connectivities different spacial arrangementsLigands & counter ions trade placesLigands coordinate in different waysDifferent spacial arrangementsMirror imagesStructural IsomersCoordination Isomers
David N. Blauch - http://www.chm.davidson.edu/vce/index.htmpentaamminesulfatochromium(III) bromidepentaamminebromochromium(III) sulfateStructural IsomersLinkage Isomers
David N. Blauch - http://www.chm.davidson.edu/vce/index.htmpentaamminenitrocobalt(III) ionpentaamminenitritocobalt(III) ionStereoisomersGeometric Isomers: cis-trans
cistransDavid N. Blauch - http://www.chm.davidson.edu/vce/index.htmcis-diamminedichloroplatinum(II)trans-diamminedichloroplatinum(II)StereoisomersGeometric Isomers: fac-merfacmer
David N. Blauch - http://www.chm.davidson.edu/vce/index.htmfac-triamminetrichlorocobalt(III)mer-triamminetrichlorocobalt(III)StereoisomersOptical IsomersMirror ImagesNon-superimposableEnantimomersChiral: optically active (rotates polarized light)
http://www.wikidoc.org/index.php/Chirality_%28chemistry%29
http://en.wikipedia.org/wiki/Chirality_%28electromagnetism%29ChiralityDetermining Optical Activity
facmerDavid N. Blauch - http://www.chm.davidson.edu/vce/index.htmChiralityDetermining Optical Activity
Superimposable - No optical activity