Textbook Reading/Sections See readings General Concepts Trends in metal and atomic radii Electronic structure of Transition metals and corresponding ions How magnetism occurs. What is para- and dia-magnetism Definition of complexes, including both inner vs. outer sphere groups. Identify atoms on a polyatomic ligand that will bind to a metal How to form a Coordinate covalent bond. How polydentate ligands do their stuff. Some thermodynamics of the chelate effect. Identify the five types of isomers discussed in class How does optical Rotation play a role in optical isomers How spectroscopy can be used to tell information about crystal field splitting of complexes. If given two structure, determine if they are isomers of each other Which d orbitals will be stabilized and destabilize by a ligand field and why! How to use the spectrochemical series for crystal field slitting understanding How to determine when a complex will be high spin or low spin based on ligands, crystal field splitting parameters and electron pairing energies. Using and calculating K f for complexes Connect thermodynamics to polydentate ligation. Main properties of each group in the periodic table: including preferred oxidation state, and simple reaction (H20, O2, Cl2 etc.) What distinguishes a metal from a non-metal Ionization energy vs. reduction potential for alkali metals Name several allotropes for key elements (e.g. O, C, P, S, Sn, etc) How to make noble gases react. Terms Poor metals Self-passivation Amphoteric Allotrope Noble gas Interhalogens Buckyballs/Nanotubes Glass Solvated Electron Metals Alkaline Earth metals Alkali Metals Amalgam diamagnetism, paramagnetism Lanthanide contraction Steel Ores High Spin/Low Spin Aufbau Principle Hund’s Rule cis, tran isomers mer, fac isomers ROYGBIV Color wheel Complementary colors Spectroscopy Crystal field splitting High field splitting ligand Coordination number Octahedral, tetrahedral, square planer, linear, bend geometries Chiral enantiomers Atomic orbital Lanthanide contraction Shielding Spin Coordination number Coordination sphere Donor atom Ligand Chelate (and chelation) Degenerate Chirality Optical active Spectrochemical series Pairing energy Hydride Nitride Oxide, superoxide, peroxide Inert pair effect Monodentate, bidentate, polydentate Stereoisomers and structural isomers Metal, non-metal, and metalloid or semi metal Ferromagnetism, paramagnetism, diamagnetism Strong field ligand and weak field ligand General Concepts Trends in metal and atomic radii Transition Metals DECREASE left to right BUT INCREASE at the end of each series (starting around 8B) Why? – When you begin to pair up the electrons in the d orbitals, the electrons begin to repel and increase the atomic radius Note: when the radius gets smaller, the density gets larger and the melting point increases (smilie face, frown, frown) Lanthanide Contraction: The 3 rd and 4 th transition metal periods have almost the same radius as the period 5 elements (2 nd row of transition metals) as the f-block electrons do a poor job shielding Electronic structure of Transition metals and corresponding ions ns 2 nd x with x=1-10 Note: these metals lose electrons from their s orbitals first (e.f, Sc: 3d 1 4s 2 Mn: 3d 5 4s 2 Exceptions (partially and full filled sub-shells): Cr: 3d 4 4s 2 -is really 3d 5 4s 1 Cu: 3d 9 4s 2 -is really 3d 10 4s 1 How magnetism occurs What is para- and dia-magnetism Paramagnetic = unpaired electrons, pulled into a magnetic field Diamagnetic = no unpaired electrons, not attracted to or repelled from a magnetic field To figure this out, find the electron configuration of the atom and draw the crystal field splitting (for d 4 -d 7 ) Note: Spin (aka magnetic moment) = # of unpaired electrons/2 Definition of complexes, including both inner vs. outer sphere groups Complex – any chemical species involving coordination of ligands to a metal center Ex. [Co(NH 3 ) 3 ] 3+ = Complex Cation Ex. [CoCl 3 (NH 3 ) 3 ] = Neutral Complex [Inner Sphere]Outer Sphere = [Metal/Ligands]Counterions (to balance charge) Identify atoms on a polyatomic ligand that will bind to a metal • See spectrochemical series Link: Ligands How to form a Coordinate covalent bond Ligands act as Lewis Bases and donate their electron pairs (both elections) to the metal atoms/ions to form coordinate covalent bonds Monodentate – donates 1 electron pair (e.g.. CN - and Cl - ) Bidentate – donates 2 electron pairs (e.g., en and ox 2 - ) Polydentate – donate 2 + electron pairs (eg., hexadentate (6 “bites”)) How polydentate ligands do their stuff. Basic thermodynamics of the chelate effect Chelation – process of a polydentate ligand attaching (“biting”) to a metal to produce a ring [Chelate = claw] Entropically favored and possibly enthalpically driven Ex. [Co(H 2 O) 6 ] + en -> [Coen(H 2 O) 4 )] + 2H 2 O 2 species 3 species Entropy increases Identify the five types of isomers discussed in class Structural: different connectivity of atoms Ionization – interchange the ions inside and outside of the coordination sphere Ex. [CrSO 4 (NH 3 ) 5 ]Cl and [CrCl(NH 3 ) 5 ]SO 4 Coordination – there is a swap in ligands between the anionic and cationic coordination spheres in a multi-coordination complex Ex. [MX][M’Y] and [MY][M’X] Linkage – differs in which atom is bound to the metal complex Ex. M-ONO and M-NO 2 Sterioisomers: different arrangement of atoms in space Geometric (cis/trans) Cis – 90° apart Trans – 180° apart Geometric (cis/trans) Mer – on the same meridian (cis-trans-cis) Fac – on the same face (cis-cis-cis) How does optical Rotation play a role in optical isomers It has NO optical isomers if: There is ANY plane of symmetry (they can be in weird places) It is invertible (you can invert the top and the bottom through the center and get the same molecule out) It is optically active and has optical isomers (entantionmers) if: The mirror image of the molecule is NONsuperimposable on the original object It is chiral How spectroscopy can be used to tell information about crystal field splitting of complexes. A wavelength corresponding to a color in the visible light spectrum is produced when a photon of light is absorbed and an electron in the d orbital is excited to a different energy state Note: d 0 and d 10 compounds are colorless (either there is no electron to excite or there is no place for the electron to go) Strong Field ligands have a large delta o and they absorb high energy light which corresponds to shorter wavelength. Shorter wavelengths of light are around violet and reflect their opposite (complementary) color. For a compound absorbing violet, the compound reflects and looks yellow Weak field ligands have a small delta o and they absorb low energy light which corresponds to longer wavelength such as red light. The complementary color is reflected and is what we see. For a compound absorbing red light we would see green (like plants!) How \(\Delta_o\) and color are related: \(\Delta_o = \dfrac{hc}{\lambda}\) Note: a compound only absorbs light when radiation from the photon has the right energy to move an electron from a low energy level to a higher one (in other words, when the above equation is true) (Crystal Field Theory concerns electrostatic attractions) If given two structure, determine if they are isomers of each other Check via optical isomer rules Look for a plane of symmetry of a point of inflection (if you find one, it is not optically active) Take the mirror image, rotate it, and see if you can superimpose it (if you can, it is not optically active) – you can’t fold the paper over! Other “Guidelines” 0 1 Octahedral Geometric Isomers ML6 NaN ML5X NaN ML4X2 (2) Cis and trans ML3X3 (2) Fac and mer MA2B2C2 (5) trans-trans-trans; trans(A)-cis-cis; trans(B)-cis-cis; trans(C)-cis-cis; cis-cis-cis (this one has an optical isomer) 0 1 Tetrahedral No Geometric Isomers – all atoms are equidistant from the center metal atom ML4 NaN ML3 NaN ML2X2 NaN MA2X2 NaN MA2XY NaN MABCD This one can have an optical isomer because all of the ligands are different 0 1 Square Planar Geometric Isomers ML4 NaN ML3X NaN ML2X2 Cis and trans ML2XY Cis and trans Which d orbitals will be stabilized and destabilize by a ligand field and why! See your discussion on Crystal Field Theory How to use the spectrochemical series for crystal field slitting understanding See your discussion on Crystal Field Theory How to determine when a complex will be high spin or low spin based on ligands, crystal field splitting parameters and electron pairing energies. • See your discussion on Crystal Field Theory Using and calculating K f for complexes Idea: ligands can “come off” and be exchanged for other ligands (preferably polydentates for monodentates due to the entropic effect) K f = K 1 *K 2 *K 3 … K f = [Products] coefficient / [Reactants] coefficients Note: This “reaction” does not occur all in one step; it occurs in multiple steps that end up canceling out to get the final K f Connect thermodynamics to polydentate ligation. Chelation – process of a polydentate ligand attaching (“biting”) to a metal to produce a ring [Chelate = claw] Entropically favored (e.g.) [Co(H 2 O) 6 ] + en --> [Coen(H 2 O) 4 )] + 2H 2 O 2 species 3 species Entropy increases Main properties of each group in the periodic table: including preferred oxidation state, and simple reaction (H 2 O, O 2 , Cl 2 etc.) See your descriptive chemistry sheet. Additional Resources - Descriptive Chemistry What distinguishes a metal from a non-metal Metal: Good conductors of heat and electricity Malleable Ductile Moderate to high melting points (except poor metals) LOSE electrons Nonmetal: Poor conductors Brittle GAIN electrons Ionization energy vs. reduction potential for alkali metals Ionization Energy is for a metal in gaseous phase Reduction potential is for a metal in its aqueous phase – hence the difference between the two “reactivities” Name several allotropes for key elements (e.g. O, C, P, S, Sn, etc) Oxygen: O, O 2 , O 3 Carbon: Graphite Fullerenes Diamond Phospohorus Red Phosphorous (3 joined together) White Phosphorous (the dangerous, less stable one) Sulfur: S 2 , S 4 , S 6 , etc. Tin Grey Tin White Tin (the one that falls apart that supposedly caused the buttons of Napoleon’s army to disintegrate in the cold Russian winter). Perhaps happened..but likely not How to make noble gases react Get a really electronegative nonmetal and high temperatures Xe + F 2 ---> XeF 2