The-d-Block-Elements-General-properties：d區(qū)元素的一般性質(zhì)課件

1、Lecture 17. The d-Block Elements.General propertiesPhD. Halina FalfushynskaLecture 17. The d-Block ElemenWhy Study Descriptive Chemistry of Transition MetalsTransition metals are found in natureRocks and minerals contain transition metalsThe color of many gemstones is due to the presence of transiti

2、on metal ionsRubies are red due to CrSapphires are blue due to presence of Fe and Ti Many biomolecules contain transition metals that are involved in the functions of these biomoleculesVitamin B12 contains CoHemoglobin, myoglobin, and cytochrome C contain FeWhy Study Descriptive ChemistrWhy Study De

3、scriptive Chemistry of Transition MetalsTransition metals and their compounds have many useful applicationsFe is used to make steel and stainless steelTi is used to make lightweight alloysTransition metal compounds are used as pigmentsTiO2 = whitePbCrO4 = yellowFe4Fe(CN)63 (prussian blue)= blueTrans

4、ition metal compounds are used in many industrial processesWhy Study Descriptive ChemistrMyoglobin, a protein that stores O2 in cells Myoglobin, a protein that storCoordination Environment of Fe2+ in Oxymyoglobin and OxyhemoglobinCoordination Environment of FeFerrichrome (Involved in Fe transport in

5、 bacteria)Ferrichrome (Involved in Fe trPeriodic Tablef block transition elementsd block transition elementsPeriodic Tablef block transitiScTiVCrMnFeCoNiCuZnYZrNbMoTcRuRhPdAgCdLaHfTaWReOsIrPtAuHgIIIBIVBVBVIBVIIBIBIIBVIIIBd-Block Transition ElementsMost have partially occupied d subshells in common o

6、xidation statesScTiVCrMnFeCoNiCuZnYZrNbMoTcRu1s2s3s4s2p3p3dEnergySc1s2 2s2 2p6 3s2 3p6 3d1 4s24p1s2s3s4s2p3p3dEnergySc4pElectronic Configurations ScAr3d14s2 TiAr3d24s2 VAr3d34s2 CrAr3d54s1 MnAr3d54s2ElementConfigurationAr = 1s22s22p63s23p6Electronic Configurations ScElectronic Configurations Fe Ar 3

7、d64s2 Co Ar 3d74s2 Ni Ar 3d84s2 Cu Ar3d104s1 Zn Ar3d104s2Element ConfigurationAr = 1s22s22p63s23p6Electronic Configurations FeGeneral Properties of the d-Block Elements and Their TrendsFourth-period d-block elements form ionic bonds with somewhat less ionic character than do the metals of the s-bloc

8、k.Lower oxidation states (+2, +3) usually correspond to ionic character.For Co through Zn, relative energies of the 4s and 3d subshells are such that few (or no) 3d electrons are lost in forming ions. For Zn, the 4s3d energy difference is so large that only 4s electrons are lost.General Properties o

9、f the d-BlThe-d-Block-Elements-General-properties：d區(qū)元素的一般性質(zhì)課件Some Properties of the Fourth Period d-BlockIn the fourth-period d-block, only scandium is active enough to displace H2 from H2O.These elements have moderate to high melting points and moderately high densities.Electrical and thermal condu

10、ctivities of these elements are very high. Copper is second only to silver in electrical conductivity.Some Properties of the Fourth Atomic Radii of thed-Block ElementsSize does not appear to increase significantly between fifth and sixth period elements.The electrons in 4f orbitals are not very good

11、 at screening valence electrons from the nucleus.Thus, the strength of attraction of valence electrons to the nucleus is greater than expected in the sixth period. The phenomenon is known as the lanthanide contraction.Atomic Radii of thed-Block ElCharacteristic properties:Color: The complexes of the

12、 d-block metal ions are usually colored, except, very often, those of d0 and d10 metal ions. The colors are due to:a) electronic transitions of d-electrons within the d sub-shell. These are known as dd transitions. d0 and d10 metal ions do not show these transitions.b) electronic transitions from th

13、e metal ion to the ligand (ML transitions) or ligand to the metal ion (LM transitions), which are known as charge-transfer transitions, and these can occur for d0 to d10 metal ions.c) The ligands themselves may be colored, and this color may contribute to the color of the complex.Characteristic prop

14、erties:ColoCharacteristic properties:Paramagnetism: When there are unpaired electrons in the d sub-shell, these will lead to paramagnetism. Thus, in Cr(H2O)63+ the three d electrons (it is d3) are unpaired. Thus, like the O2 molecule which is paramagnetic, Cr(III) is paramagnetic. A d10 metal ion (e

15、.g. Zn(II) has a filled d sub-shell, and a d0 metal ion (e.g. Ti(IV) has no d-electrons, so neither of these can be paramagnetic. Variable oxidation states: Most d-block metal ions display variable oxidation states. Thus, for example, Mn displays oxidation states from Mn(-III) (in Mn(CO)(NO)3) throu

16、gh Mn(0) (in Mn2(CO)10) to Mn(VII) (in MnO4-). Characteristic properties:ParaOxidation states of first-row d-block ions:Sc TiVCrMnFeCoNiCuZn11111112222222223 333333334444444455556667The most stable oxidation states are in red, rarer oxidation states pale blue:These achievethe groupoxidation stateThe

17、 higher oxidat-ion states become progressIvely less stable as the divalent state becomes dominantMaximum at Mn(VII) 3 4 5 6 7 8 9 10 11 12 Oxidation states of first-row loss of ns e-sloss of ns and (n-1)d e-sloss of ns e-sloss of ns and (Electronic configuration of Fe3+Electronic configuration of Fe

18、2+Fe 2e- Fe2+ Ar3d64s2 Ar3d6Fe 3e- Fe3+ Ar3d64s2 Ar3d5valence ns e-s removed first, then n-1 d e-sElectronic Configurations of Transition Metal Ionsvalence ns e-s removed firstElectronic configuration of FeCharacteristic properties:Complex-formation: The d-block metal ions form a wide variety of complexes, of generally high stability, with ligands such as EDTA or F-, Cl-, and OH-, or ethylene diamine (en), as well as many others, much as was the c