Kotz and Triechel, Chemistry and Chemical Reactivity Chapter 22: Sections 1-6.
- 22.1 Properties of the transition elements: Most transition elements are solid (the only exception is mercury) and shiny, ductile, malleable, excellent heat and electrical conductors, and they react variously with oxidizing agents to form ionic compounds. They are important catalysts in biological reactions, important pigments in paints and dies, and they provide color in many gems and semiprecious stones. Transition elements all have d orbitals with 1 to 10 electrons, and 1 to 2 s orbital electrons at a higher energy level, which are removed during oxidation. Metal ions frequently have oxidation numbers of two or three, matching their ionic charge. Radii, density, and melting point increase across the road to the midpoint, then drop.
- 22.2 Metallurgy is the technology for extracting metals from ores and creating alloys. Copper, silver, and gold occur in nature as free elements; most others occur as oxides, sulfides, halides, or carbonates. Pyrometallurgy (high temperature reactions) and hydrometallurgy (aqueous solutions) are both used to extract care metals from their ores. The ores may then be recombined with other elements to adjust flexibility, hardness, strength, and malleability. In particular, iron is combined with carbon to form steel.
- 22.3 Coordination compounds are structural units containing coordination complexes. These molecular units are solid ionic compounds containing both cations and anions arranged in a regular array (all hydrates fall into this category). A central metal ion forms ionic bonds to other molecules or ions (ligands), resulting in a neutral or ionic complex. Ligands which attached to the central ionized metal atom with more than one bond are polydentate or chelating ligands. Chelating ligands such as hemoglobin and chlorophyll play important roles in biochemistry. Because of their importance, coordination compounds have specific naming conventions.
- 22.4 Coordination compound structures can very geometrically. Molecules with the same chemical formula but different geometric structures are isomers.
- Structural isomers
- Coordination isomers occur when it is possible to exchange a coordinated ligand and the uncoordinated counter ion, as with [Co(NH3)5Br]SO4 and [Co(NH3)5SO4]Br.
- Linkage isomers occur when the ligand can be attached to the metal through different ions. For example, thiocyanate (SCN-) contains sulfur and nitrogen, each with a lone pair, either of which can be used to bind to a metal ion to form a coordination compound.
- Geometric isomers
- Cis-trans isomers involve complexes where ligands of similar types may be on the same side or opposite sides of the central metal ion. The chemical properties of cis and trans forms may be radically different.
- Fac and mer isomers involve ligands which form cube units with components on the corners (fac) or in the middle of the face (meridian or mer).
- Optical isomers form when a central metal ion binds to three or more ligands, each of which has at least two binding sites. Geometrically, the coordination compound can have a mirror-image. Complexes with this property are chiral.
- 22.5 Two theories are used to explain bonding in coordination compounds. we are already familiar with molecular orbital theory which explains bonds as overlapping π and σ orbitals between atoms, but it does not account for all observed phenomena. Ligand field models may be used to explain ligand bonds in terms of electrostatic attraction and repulsion and electron spin within orbitals (d-orbital splitting), to account for slight differences in energy levels that affect bond strength, conductivity, and magnetic properties.
- 22.6 The colors of coordination compounds may also be explained in terms of de-orbital splitting. Where d-orbital separation Δ0 is large, the complex is able to absorbe a large amount of energy in a single photon; therefore those complexes with the greatest orbital splitting absorb light with the lowest wavelengths (highest frequency, greatest energy).
If you find these study methods useful, visit the Chapter 22 resources at Cengage "Brain" companion site for our text. Click on the chapter dropdown and select Chapter 22 to use the flashcards and glossary.
Use the MindTap reader version of the textbook to view videos and test your understanding with interactive checkpoints. Check OWLv2 for your homework problems.
Videos for Chapter 22: Principles of Chemical Reactivity: Transition Group Elements
Review the Videos at Thinkwell Video Lessons.
- Under "CHEMISTRY OF METALS"
- An Introduction to Metals
- Under "TRANSITION METALS"
- Examining Transition Metals
- Properties of Transition Metals
- Coordination Compounds
- Complexes and Ligands
- Naming Coordination Compounds
- Structures of Coordination Compounds and Isomers
- Coordination Compounds
- Color and Transition Metals
- Ligand Field Theory
Homework problems: See your Moodle assignment!
AP LAB #18 GUIDED INQUIRY — — GUIDED INQUIRY —
Titration quantitative analysis methods — Phase I
Choose two different common household chemicals such as a food juice, vinegar, or cleaning solution. Select an appropriate method to measure the expected pH range, and design a procedure to analyze of the acidity of your items, (e.g., using titration acid-base or redox methods).
- APGIE Investigation 4: How much acid is in Fruit Juices and Soft Drinks
- APGIE Investigation 3: What Makes Hard Water Hard?
- IGHCE Lab 20.1 Quantitative Analysis of Vitamin C
- AP2009 8 Determination of Concentration by oxidation-reduction reactions
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