Compounds & Chemical Bonds View: How atoms bond George Zaidan and Charles Morton

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 a nonmetal and a metal combine, they form an ionic bond: Valence electrons of the metal are lost and the nonmetal gains these electrons to achieve a Noble gas electron configuration.  When two nonmetals combine, 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

Ionic vs. Covalent Bonding

Electronegativity

Periodic Table Properties & Organization

Periodic Table Properties & Organization

QUESTION

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 - )

Electron Configurations

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?  Mg 2+ and Cl   1 Mg 2+ combines with 2 Cl  MgCl 2

Predict the formula for the binary ionic compound formed by aluminum and oxygen. A) Al 2 O 3 B) Al 3 O 2 C) Al 2 OD) AlO 2 QUESTION

Ionic vs. Molecular (Covalent) Compounds Salt (ionic) vs. Water (covalent)

Covalent Chemical Bonds Molecular Compounds View: Hank Green Crash Course

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 Notes from Lewis’s notebook and his “Lewis” structure. Footnote: G.N. Lewis, despite his insight and contributions to chemistry, was never awarded the Nobel prize.

Lewis Electron-Dot Drawings Periods 2 & 3 Eg. Ammonia:

Shapes of Molecules View: What is the shape of a molecule? George Zaidan and Charles Morton

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 C =black H = gray N = blue O = oxygen pink = generic atom swf/vsepr_four_electron.htm

Polyatomic Ions Discrete units of covalently bonded atoms that behave as ions

Which formula containing polyatomic ions is correct? A) MgNO 3 B) NH 4 CO 3 C) Na(PO 4 ) 3 D) Al 2 (SO 4 ) 3 QUESTION

Chemical Formulas & Molecular Representations

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.

Structural Representations of Quinine

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 Structure-Odor Relationships Karen J. Rossiter, Chem. Rev., 1996, 96,

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"

Shapes & Interactions: Mirror Images & Smell S-(+)-d- R-(-)-l- S-(+)- carawayR-(-)- spearmint