CHEMISTRY - CLUTCH CH.23 - TRANSITION METALS AND COORDINATION COMPOUNDS

Transcription

1 H.23 - TRANSITIN METALS AND RDINATIN MPUNDS!!

2 H.23 - TRANSITIN METALS AND RDINATIN MPUNDS NEPT: THE TRANSITIN METALS The transition metals represent elements found in the block of the periodic table. Whereas the main group elements show similar chemical behavior because of their valence electrons, transition metal similarities are treated differently. Transition metals show great chemical similarities in both their horizontal and their vertical. In the gradual addition of electrons to transition metals new electrons are added to the inner core electrons, which do not participate in chemical bonding. For transition metals each additional electron is added to the block orbitals, while for lanthanides and actinides they are added to the block orbitals. Page 2

3 H.23 - TRANSITIN METALS AND RDINATIN MPUNDS NEPT: PRPERTIES F TRANSITIN METALS Like most main group metals the transition metals possess similar physical properties such as: luster, high densities, good electrical and thermal conduction, melting points and hardness. onduction possesses the greatest electrical conduction with coming in second. Melting Point possesses the highest melting point at 3400 o, while is the only metal that is a liquid at room temperature. Hardness Metals such as and are strong, but other metals such as, and are considered soft. xidation States Remember that transition metals possess variable charges and so the use of is necessary to identify the correct charge of the element. Page 3

4 H.23 - TRANSITIN METALS AND RDINATIN MPUNDS NEPT: ELETRN NFIGURATIN F TRANSITIN METALS Electron configurations are a representation of how electrons are distributed into orbitals and furthermore how those orbitals fit into different energy levels. 1s 2s$$$$$$2p 3s$$$$$$3p$$$$$$3d 4s$$$$$$4p$$$$$$4d$$$$$4f 5s$$$$$$5p$$$$$$5d$$$$$5f$$$$$5g 6s$$$$$$6p$$$$$$6d$$$$$6f$$$$$6g$$$$6h$ 7s$$$$$$7p$$$$$$7d$$$$$7f$$$$$7g$$$$7h Recall there are exceptions that exist with the electron configuration of transition metals that end with or. These exceptions are normally observed with only the transition metals. EXAMPLE: Write the condensed configuration for the following element: hromium (24 electrons) Page 4

5 H.23 - TRANSITIN METALS AND RDINATIN MPUNDS PRATIE: ELETRN NFIGURATIN F TRANSITIN METALS EXAMPLE: Write the condensed electron configuration of the following element. W EXAMPLE: Write the condensed electron configuration of the following ion. Mn 4+ EXAMPLE: Write the condensed electron configuration of the following ion. Fe 6+ Page 5

6 H.23 - TRANSITIN METALS AND RDINATIN MPUNDS NEPT: TRENDS IN ATMI SIZE Recall it going from left to right across a period and going down a group. For transition metals, when moving across a period the size for the most part remains constant. Ex: When moving from the 3d transition metals to the 4d transition metals we see a (n) in atomic radius, but moving from 4d to 5d the pattern is quite different and stays relatively constant. This phenomenon is referred to as the lanthanide contraction. Page 6

7 H.23 - TRANSITIN METALS AND RDINATIN MPUNDS NEPT: TRENDS IN INIZATIN ENERGY Recall it going from left to right across a period and going down a group. However when moving down a group we see that the ionization energy of the third row is higher than the first and second row. This opposite trend is the result of the element s. Page 7

8 H.23 - TRANSITIN METALS AND RDINATIN MPUNDS NEPT: TRENDS IN XIDATIN STATES As we ve stated in the past oxidation involves electrons. ne of the most common features of transition metals is that they possess multiple oxidation states. x. State 3B (3) 4B (4) 5B (5) 6B (6) 7B (7) 8B (8) 8B (9) 8B (10) 1B (11) 2B (12) Sc Ti V r Mn Fe o Ni u Zn 0 þ þ þ þ þ þ þ þ þ þ +1 þ þ þ þ þ þ þ +2 þ þ þ þ þ þ þ þ þ +3 þ þ þ þ þ þ þ þ þ +4 þ þ þ þ þ þ þ +5 þ þ þ þ +6 þ þ þ +7 þ Page 8

9 H.23 - TRANSITIN METALS AND RDINATIN MPUNDS PRATIE: TRENDS IN XIDATIN STATES EXAMPLE 1: Determine the oxidation state of the underlined element: [Ni(H2)6]l2. EXAMPLE 2: Determine the oxidation state of the underlined element: [o(nh3)4(h2)br]br2. PRATIE 1: In which compound does Ti exhibit greater metallic behavior: TiF2 or TiF6? PRATIE 2: Which oxide, r3 or r, forms a more acidic aqueous solution? Page 9

10 H.23 - TRANSITIN METALS AND RDINATIN MPUNDS NEPT: RDINATIN MPUNDS The most prevalent aspect of transition metal chemistry is the formation of coordination compounds or complexes. Within a coordination complex there is at least one, a species that is made of a metal cation that is connected to molecules and/or anions called. In order to maintain the overall neutrality of the compound, are used. [Ni(NH 3 ) 4 ]l 2 RDINATIN NUMBERS The coordination number is the number of ligand atoms bonded to the central metal cation. The coordination number is based on the of metal cation and its. The most common coordination number is, however 2 and 4 are also common. GEMETRIES The types of geometries allowed are based on the coordination number of the central metal ion. oordination Number Shape Linear Tetrahedral Square Planar ctahedral Page 10

11 H.23 - TRANSITIN METALS AND RDINATIN MPUNDS PRATIE: RDINATIN MPUNDS EXAMPLE 1: Determine the geometry for the following complex ion: [Zn(NH3)4] 2+. EXAMPLE 2: Determine the geometry for the following complex ion: [AuBr2]. PRATIE: Determine the geometry for the following complex ion: [r(nh3)4l2] 2+. Page 11

12 H.23 - TRANSITIN METALS AND RDINATIN MPUNDS NEPT: LIGANDS A ligand can be thought of as a because it bonds to a central metal cation in a complex ion by using its lone pair. Ligands are characterized by the number of elements in the molecule that can donate a lone pair. These compounds use this lone pairs to grab onto these metal cations and are referred to as agents. Ligands that possess only element(s) able to donate a lone pair are referred to as monodentate ligands. Monodentate ("ne-toothed") H 2 X N H NH 3 S N N or or Ligands that possess element(s) able to donate a lone pair are referred to as bidentate ligands. Bidentate ("Two-toothed") 2 H 2 H 2 H 2 N NH 2 Page 12

13 H.23 - TRANSITIN METALS AND RDINATIN MPUNDS Ligands that possess element(s) able to donate a lone pair are referred to as polydentate ligands. Polydentate ("Many-toothed") 5 H 2 H 2 H 2 H 2 P P P H 2 N N H Diethylenetriamine NH 2 Triphosphate ion 4 H 2 N H 2 H 2 H 2 N H 2 H 2 Ethylenediaminetetraacetate ion (EDTA 4 ) Page 13

14 H.23 - TRANSITIN METALS AND RDINATIN MPUNDS NEPT: NAMING RDINATIN MPUNDS In the early days of coordination compounds they were named after the person who first prepared them or for their brilliant colors. Today, the naming of coordination compounds is similar to naming ionic compounds. Rules for Naming: a. The metal cation is written before the nonmetal anion. If the metal is a transition metal we must use a to describe its positive charge. The only space in the name should appear between the and the. b. For the complex ion portion, neutral ligands are written before anionic ligands, and the formula for the whole ion is placed inside of brackets. Within the complex ion, the ligands are named in alphabetical order before the metal ion. Anionic ligands drop the ide and add o after the root name. Neutral Ligands Anionic Ligands Formula Name Formula \ H2 Aqua Fluoro F Name NH3 Ammine hloro l arbonyl Bromo Br N Nitrosyl Iodo I Hydroxo H yano N Page 14

15 H.23 - TRANSITIN METALS AND RDINATIN MPUNDS c. A numerical prefix is used to determine the number of a particular ligand. d. If the complex ion is an anion, we replace the ending of the metal name and add ate. omplex Anions Metal Iron (Fe) opper (u) Lead (Pb) Silver (Ag) Gold (Au) Tin (Sn) Name in Anion Ferrate uprate Plumbate Argentate Aurate Stannate [Ti(NH 3 ) 4 Br 2 ]Br Na[Pt(NH 3 ) 3 l 5 ] Page 15

16 H.23 - TRANSITIN METALS AND RDINATIN MPUNDS PRATIE: NAMING RDINATIN MPUNDS EXAMPLE 1: Give the systematic name for the following formula: Na[Ag(N)2]. EXAMPLE 2: Give the formula based on the given name: Tetraamminezinc carbonate PRATIE 1: Give the systematic name for the following formula: [o(nh3)4(h2)l]l2. PRATIE 2: Give the formula based on the given name: Lithium bis(thiosulfato)argentate (I) Page 16

17 H.23 - TRANSITIN METALS AND RDINATIN MPUNDS NEPT: STRUTURE AND ISMERISM Isomers are compounds that possess the same molecular formula, which means they have the same atoms, but they differ in their location of each atom. ISMERS formula but structures Different onnections Same onnections NSTITUTINAL ISMERS STEREISMERS oordination Isomers Ligand and/or counterion swapping With Stereocenters Without Stereocenters PTIAL ISMERS GEMETRI ISMERS Linkage Isomers Difference in Donor Atom Enantiomers Nonsuperimposable mirror images is/trans Isomers (Diastereomers) Different spatial arrangements Page 17