Friday, June 19, 2015

The pillars of chemistry

The pillars of chemistry


1st Pillar = We encounter atoms on the mole (macroscopic) scale
Chemistry is dictated by individual atoms interacting on the macroscopic scale
We must be able to deal with both scales

2nd Pillar = Systems in nature usually seek the lowest Energy possible
Almost all of chemistry is based on the interaction of charges seeking the lowest Energy

3rd Pillar = "Periodic Law"
arranged by atomic number, elements exhibit periodicity in their properties
elements grouped by properties

4th Pillar = electron motion in atoms is guarenteed
it occurs acoording to discrete functions, only at discrete energies


 “The Six Pillars of Organic Chemistry”


  • Electronegativity – in an example provided, going across a period  leads to increasing nucleophilicity with decreasing electronegativity. For example, nucleophilicity follows the following order:
  • Polar covalent bonding – when bonds form between atoms of unequal electronegativity, the resulting dipole has a positively charged terminus and a negatively charged terminus, which will provide insight into its preferred mode of chemical re-activity. So in the above example, the C-Cl bond is polarized whereas the C-H bonds (C and H having relatively similar electronegativities) are not, resulting in selective breakage of the carbon-halogen bond during the SN2 instead of the carbon-hydrogen bonds.
  • Steric effects – the rate of the SN2 is greatly affected by the presence of neighboring bulky groups. So the trend for the above reaction would be:
  • Inductive effects. The author gives the example of Markovnikoff’s rule as an example of inductive effects, where increasing substitution on carbon leads to increasing inductive stabilization of the carbocation [he also notes that hyperconjugation, a more fundamentally sound explanation, can be covered in the resonance section, below].
  • Resonance – resonance effects are widespread in organic chemistry. One example is that they explain the selective bromination of cyclohexene at the allylic position under free-radical conditions, versus competing bromination at the secondary (or vinylic positions). Another example is the planarity of peptide bonds due to the π donation of electrons into the carbonyl π* orbital.
  • Aromaticity – Aromaticity is an important driving force in chemical reactions and a powerful stabilizing influence on molecules. The decreased reactivity of benzene in bromination reactions versus, say, cyclohexene is an extension of resonance stabilization, which helps to explain why tryptophan is not considered a basic amino acid even though (like lysine) it contains a nitrogen – in tryptophan, the nitrogen lone pair is tied up in the π system.
  • CHEMISTRY



    Purpose

    Goal of chemistry is to familiarize with matter, its components, and the changes it undergoes.

    Objective




  • Understand the definition of chemistry.
  • Explain the role of energy in chemistry.
  • Know the physical characteristics, chemical characteristics and states of matter.
  • Learn the metric system and SI units.
  • Determine precision, accuracy and significant figures.
  • Explore the development of the modern atomic theory
  • Investigate the mysteries of the quantum theory
  • Discover the quantum mechanics
  • Learn how to write electron configurations and orbital notations
  • Comprehend the role of the electron in chemical reactions
  • Discover the 7 Secrets of periodic table
  • Understand chemical bonding and molecular geometry
  • Learn how to name and write chemical formulas
  • Describe acids and bases
  • Recognize chemical reactions and predict the products
  • Grasp Avogadro’s number and the mole concept
  • Perform stoichiometric calculations
  • Learn and use the gas laws
  • Study solutions, molarity and molality


  • “There’s an old saying, “Repetition is the Mother of Skill,” meaning that in order

    for you to improve or increase your performance, you need to
    practice the fundamentals over and over again.”


    Skills

    • Learn to use the calculator as a tool
    • Sharpen your algebra skills
    • Develop problem-solving skills
    • Master naming compounds
    • Master writing chemical formulas
    • Learn to write chemical equations

    Laboratory

    • Learn and use safe lab procedures
    • Name and use lab equipment
    • Learn to observe
    • Develop skills for accurate record keeping
    • Learn how to use a laboratory notebook
    mrcausey.com






    http://mrcausey.net/mrcausey/chemistry/chem_units/

    Scientific Method

    Lab Safety
    Introduction to Chemistry
    Scientific Method
    Experimental Process

    Molecular Geometry

    Molecular Geometry
    Inter-molecular Forces
    Hybridization
    Calculations and Sig Figs

    Calculations

    Scientific Notation
    Significant Figures
    Unit Analysis
    Calculations

    Chemical Nomenclature

    Naming Ionic Compounds
    Naming Covalent Compounds
    Naming Acids
    Writing Formulas

    Divisions of Matter

    Properties of Matter
    Density and Specific Gravity
    Phases of Matter

    Chemical Reactions

    Chemical Reactions
    Writing Chemical Reactions
    Balancing Equations

    Atomic Models

    The Electron and Atomic Models
    Solid Sphere Model and John Dalton
    Plum Pudding Model and JJ Thomson
    Nuclear Model and Ernest Rutherford

    Avogadro's Number and the Mole

    Avogadro's Number
    The Mole
    The Mole Ratio
    Molar Mass

    Planetary Model

    Light as a Wave
    EMR Spectrum
    Light as a Particle
    Planetary Model and Niels Bohr

    Stoichiometry

    Stoichiometry
    Percent Composition
    Limiting Reactants

    Quantum Model

    Wave Mechanical
    Quantum Mechanical
    Quantum Numbers

    Concentration

    Concentration
    Molarity
    Molality

    Electron Arrangements

    Electron Configuration
    Orbital Notation
    Writing Quantum Numbers

    Valence Electrons

    Valence Electrons
    Lewis Dot Symbols
    Octet Rules
    Oxidation Numbers

    The Periodic Table

    Periodic Table Secrets
    Periodic Trends
    Ionization Energy
    Electronegativity

    Chemical Bonding

    Chemical Bonding
    Ionic bonding
    Covalent Bonding
    Metallic Bonding