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Compounds & Chemical Bonds. View: How atoms bond George Zaidan and Charles Morton. https://www.youtube.com/watch?v=NgD9yHSJ29I. Compounds & Chemical Bonds.
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Compounds & Chemical Bonds View: How atoms bond George Zaidan and Charles Morton https://www.youtube.com/watch?v=NgD9yHSJ29I
Compounds & Chemical Bonds Atoms in a compound (molecule) are in ratios of whole numbers with specific 3-dimensional arrangements due to attractive inter-atomic forces (Bonds). These provide favorable energy states & spatial positions (lower energy & farther apart are better), which result in molecules having new chemical, physical, and biological properties.
Electrons, Configurations, & Bonds Noble Gases and The Rule of Eight • When anonmetaland a metal combine, they form an ionic bond: Valence electrons of the metalare lost and the nonmetal gains these electrons to achieve a Noble gas electron configuration. • When two nonmetalscombine, they form a covalent bond: They share electrons to achieve a Noble gas electron configuration.
Compounds & Chemical Bonds View: Types of Chemical Bonds Hank Green / Crash Course https://www.youtube.com/watch?v=QXT4OVM4vXI
Periodic Table Properties & Organization http://chemconnections.org/general/movies/html-swf/periodictrends.htm
Periodic Table Properties & Organization http://chemconnections.org/general/movies/html-swf/periodictrends.htm
Number of Valence Electrons for Elements in the “A” lettered Vertical Columns Equal the Column Number
Ionic Bonds • Result from electrostatic attractions of closely packed, oppositely charged ions. • Form when an atom, which can easily lose electrons reacts with one which has a high electronegativity, that is, it can easily gain electrons. The vertical A column number (# of valence electrons) in the Periodic Table indicates the ion that forms and the number of electrons gained or lost. • Eg. Na (-1e-) and Cl (7e-; +1 e-); Mg (-2e-) and Br (7e-; +1 e-) ; K (-1e-) and O (6e-; +2 e-)
Ionic Compounds • Neutrally Charged • Eg. Salt: NaCl 1 Na+ and 1 Cl - • What is the proportion of ions for a compound formed from Mg ion and chlorine? • Mg2+and Cl • 1 Mg2+combines with 2 Cl MgCl2
QUESTION • Predict the formula for the binary ionic compound formed by aluminum and oxygen. • A) Al2O3 B) Al3O2 C) Al2O D) AlO2
Ionic vs. Molecular (Covalent) Compounds Salt (ionic) vs. Water (covalent) http://chemconnections.org/general/movies/html-swf/comp_molec_ionic_co.htm
Covalent Chemical BondsMolecular Compounds View: Hank Green Crash Course https://www.youtube.com/watch?v=bD-SH1ASbjw
Lewis Structures (Named after Prof. G. N. Lewis UC Berkeley) • Show how valence electrons are arranged among atoms and in a molecule; particularly useful for covalent molecules. • Reflects central tenet that stability of a compound relates to noble gas electron configuration. • Shows bonds and relates to 3-dimensional shapes in molecular structures.
G.N. Lewis Photo Bancroft Library, University of California/LBNL Image Library Footnote: G.N. Lewis, despite his insight and contributions to chemistry, was never awarded the Nobel prize. Notes from Lewis’s notebook and his “Lewis” structure.
Lewis Electron-Dot Drawings Periods 2 & 3 http://chemconnections.org/general/movies/LewisDotStructures.swf Eg. Ammonia:
Shapes of Molecules View: What is the shape of a molecule?George Zaidan and Charles Morton https://www.youtube.com/watch?v=Jq_Ca-HKh1g
Lewis Structures / VSEPR Molecular Models for C, H, N, O • Fundamental repeating shapes found in every biological molecule • C =black • H = gray • N = blue • O = oxygen • pink = generic atom
Lewis Structures / VSEPR Molecular Models for C, H, N, O • Fundamental repeating shapes found in every biological molecule http://chemconnections.org/general/movies/html-swf/vsepr_four_electron.htm C =black H = gray N = blue O = oxygen pink = generic atom
Polyatomic Ions Discrete units of covalently bonded atoms that behave as ions http://chemconnections.org/general/chem120/polyatomics.html
QUESTION Which formula containing polyatomic ions is correct? A) MgNO3 B) NH4CO3 C) Na(PO4)3 D) Al2(SO4)3
How many hydrogens, oxygens, and carbons are there in: ethanol? ethylene glycol? aspirin? Red spheres are oxygen, the white/gray are hydrogen, and black carbon.
Proteins & Small Molecules The interaction of a large protein bio-polymer, acetylcholinesterase, with a relatively small molecule of acetylcholine. A general process similar to the way that scientists that think we smell and many physiological processes.
Detecting stuff we cannot see: the Sense of Smell Models, Theories & Interactions http://ep.llnl.gov/msds/orgchem/Chem226/smell-links.html Structure-Odor Relationships Karen J. Rossiter, Chem. Rev., 1996, 96, 3201-3240
Historical view of a few smell receptors. 4 October 2004 The Nobel Assembly at Karolinska Institutet has today decided to award The Nobel Prize in Physiology or Medicine for 2004 jointly to Richard Axel and Linda B. Buck for their discoveries of "odorant receptors and the organization of the olfactory system" http://dvcchem.org/COT/chemical-communication/ChemComm.html
Shapes & Interactions: Mirror Images &Smell S-(+)-d- R-(-)-l- S-(+)- caraway R-(-)- spearmint http://ep.llnl.gov/msds/orgchem/Chem226/Smell-Stereochem.html