BIOS 208 1st Edition Lecture 6Outline of Last Lecture I. Biological Uses of IsotopesII. Isotope radiometric datingIII. Shroud of TurinIV. Chemical Bonds and Electron OrbitalsV. Electron ShellsVI. Periodic TableOutline of Current Lecture I. Covalent bondsII. Oxygen O2III. Ionic BondsIV. Carbon and the Molecular Diversity of Life V. The End of Vitalism in ChemistryCurrent LectureI. Covalent bondsA. 2 atoms share one or more pairs of e-.B. Bonds are directional and specific: bonded atoms cannot bond with any other atoms.C. Bonds are strong.D. Need Energy to break bonds.E. Energy is released when bonds are formed.II. Oxygen O2A. Atomic number is 8.B. First shell has 2 e- and thismeans there are 6 e- in 2nd (outer) shell.C. The covalent bond shares two electron pairs, O = O and makes a double bond stronger.D. Bond is directional and specific.E. Atoms form covalent bonds to complete their valence shells with the same element, or different elements, and forming single, double, or triple bonds.a) H2 H2O CH4 O2N2.III. Ionic BondsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.A. Na and Cl as an example:a) Na and Cl both have incomplete outer shells and also have unpaired electrons.b) If Na gives up 1 e- and Cl gains (steals) 1 e- then Na and Cl exist as IONS.c) Na+ has 11P and 10 electrons Cl-has 17P and 18 electrons.B. Ions are charged atoms.C. Loss of e- gives + charged cations (Na+).D. Gain of e- gives – charged anions (Cl-).E. One atom strips away a valence electron from its partner.F. Opposite charges attract. G. Once ionic bond forms, atoms have filled valence shells, and the compound is electro-neutral.IV. Carbon and the Molecular Diversity of LifeA. Most of the dry weight of organisms consists of carboncompounds.B. Organic chemistry primarily involves the chemistry of carbon reactions.C. e.g. CO2 and simple molecules like organic acids to very complex large proteins with high molecular weights greater than 100,000 Daltons.D. The major elements of living organisms are C, O, H, N, P, and S.E. Carbon is tetravalent 6C it needs 4 more electrons in its outermost shell.V. The End of Vitalism in ChemistryA. Jons Berzelius MD 1802…the boss said organic chemicals could notbe made without living organisms.B. Student Wohler made urea out of ammonium cyanate in
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