2.5 Transition metals

• Transition metals form a variety of different ions
• Transition metals have variable oxidation states
• Transition metals form colored ions in solution
• Transition metals have the ability to form complex ions
• The color directly opposite the absorbed color on the color wheel is the one that has been absorbed
• Transition metal complexes absorb specific frequencies of light, resulting in the perception of complementary colors
• Colorimetry is used to analyze transition metal complexes and measure the concentration of colored substances
• Redox titrations can be used to calculate the concentration of a reagent
• Titration values should be recorded to two decimal places
• Increasing the surface area of a heterogeneous catalyst can increase the rate of reaction
• Heterogeneous catalysts are in a different phase from their reactants
• Using a calibration graph to measure the concentration of a sample based on its absorbance
• Different ligands can form different strength bonds with the metal ion
• Substitution reactions of transition metals can result in color changes
• Ligands of different sizes can lead to changes in coordination number and shape of the complex
• Transition metals have variable oxidation states, form colored ions in solutions, and are good catalysts
• Zinc is not a transition element because its d subshell remains full in its stable ion, zinc 2+
• Scandium is not a transition element because its d subshell is not partially filled in its stable ion, scandium 3+
• Redox potentials can be influenced by ligands and pH.
• The least stable ions have the largest redox potential and are more likely to be reduced.
• Copper two-plus ion has a higher redox potential than zinc.
• Tollens reagent has a large redox potential, making the reduction of silver ions to silver metal likely.
• Mirror image isomers are molecules that are mirror images of each other but are non-superimposable.
• Square planar complexes can also exhibit cis-trans isomerism.
• Octahedral complexes with three bidentate ligands can show optical isomers.
• Sis-trans isomerism is a type of stereoisomerism found in complex molecules with a different arrangement of atoms in space.
• D orbital splitting occurs when ligands are bonded to a metal ion, causing the splitting of the D orbitals into different energy levels.
• Transition elements have a partially filled d subshell
• Excited state is where an electron moves to a higher energy level orbitals
• An example is the hexa aqua copper complex, which absorbs red light
• The larger the energy gap (ΔE), the higher the frequency of light absorbed
• The energy absorbed by electrons can be calculated using the formula: ΔE = H * μ * λ / c
• Only frequencies that are absorbed create a complementary color
• Hemoglobin contains an iron ion, which is a transition metal.
• Hemoglobin is a protein that transports oxygen in red blood cells.
• In the lungs, oxygen substitutes the water ligands in hemoglobin, allowing it to transport oxygen.
• Water molecules that were previously attached to hemoglobin are expelled from the body when breathing out.
• Hemoglobin has an octahedral shape and the ligand heme forms four coordinate bonds with the iron ion.
• One of the coordinate bonds in hemoglobin comes from the protein globin, while the other comes from either an oxygen or water molecule.
• The size of the ligands determines the shape of the complex, while the coordination number is the number of coordinate bonds in the complex.