HTML University

Science Dept.

Biology BIO 100
Some Chemistry

1. Introduction
   1. Democritus (460-370 BC): "Atoms" Different for Each Kind of Matter

   2. Boyle 1661: Atomic Concept to Explain Behavior of a Gas

   3. Dalton 1808: Atomic Concept

   4. Atom: Can Not Be Broken Down into Simpler Substances by Ordinary Chemical Means

   5. Element: A Pure Homogeneous Substance that Can Not Be Broken Down into Simpler Substances by Ordinary Chemical Means

   6. Element: A Collection of the Same Kind of (Element) Atom

   7. Chemical Symbols: eg H, C, O, N, K, P, Ca, S, Mg, Cl, Na

2. Atomic Structure
   1. Nucleus of an Atom
      1. Has the Positive Charge of the Atom

      2. Most of the Atom's Mass

      3. Much Smaller than the Atom

      4. Composed of Protons, p⁺ and Neutrons, N^o

   2. Atomic Number = Number of Protons = # of p⁺

   3. Atomic Weight or Mass = Number of Protons + Number of Neutrons

   4. For Example ¹²₆C, Where 12 Is the Atomic Weight and 6 Is the Atomic Number

   5. Isotopes Such as ¹₁H Hydrogen, ²₁H Deuterium, ³₁H Tritium

   6. The Electron e^-, Where Is It?

   7. Mass of an e^- Is Roughly 1/2000 mass of a p⁺

   8. Mass of a Neutron ~= Mass of a p⁺ + e^-

3. Orbitals for Electrons
   1. First Orbital Has 2 Electrons (2 e^-)

   2. Second Orbital Has 8 Electrons (2 e^-, 6e^-)

   3. Third Orbital Has 18 Electrons (2 e^-, 6e^-, 10e^-)

   4. Stable Octet

   5. Noble or Inert Gases

   6. N.B. "Periodicity"

   7. N.B. Families or Groups

   8. Dimetri Mendeleev and the Periodic Table of the Elements

4. Drawing Orbitals
   1. Draw the Electrons in Their Orbits for Hydrogen

   2. Draw the Electrons in Their Orbits for Helium

   3. Draw the Electrons in Their Orbits for Lithium

   4. Draw the Electrons in Their Orbits for Beryllium

   5. Draw the Electrons in Their Orbits for Boron

   6. Draw the Electrons in Their Orbits for Carbon

   7. Draw the Electrons in Their Orbits for Nitrogen

   8. Draw the Electrons in Their Orbits for Oxygen

   9. Draw the Electrons in Their Orbits for Fluorine

   10. Draw the Electrons in Their Orbits for Neon

   11. Draw the Electrons in Their Orbits for Sodium

   12. Draw the Electrons in Their Orbits for Magnesium

5. Questions
   1. What Would the Na Atom "Configuration" Look Like?

   2. What Would the Charge Be on Na If It Lost One Electron?

   3. What Would the Na Ion "Configuration" Look Like?

   4. What Would the Mg Atom "Configuration" Look Like?

   5. What Would the Charge Be on Mg if It Lost Two Electrons?

   6. What Would the Mg Ion "Configuration" Look Like?

   7. What Would the F Atom "Configuration" Look Like?

   8. What Would the Charge Be on F if It Gained One Electron?

   9. What Would the F Ion "Configuration" Look Like?

6. Compounds
   1. A Pure Homogeneous Substance that Can Be Broken Down into Simpler Substances by Ordinary Chemical Means

   2. Two or More Atoms Held Together by Some Form of Chemical Bond

   3. NaCl Is an Ionic Compound

   4. H₂O Is a Covalent Compound

7. Ions and the Ionic Bond
   1. 2Na + Cl₂ ---> 2Na¹⁺ + 2Cl^1-

   2. Na ---> Na¹⁺ + e^1-

   3. Cl + e^1- ---> Cl^1-

   4. The Na¹⁺ and the Cl^1- Ions Have a Mutual Electrostatic Force of Attraction Called an Ionic Bond

8. Covalent Bond
   1. What About H Combining with H? Can there Be Ions?

   2. Since Each Hydrogen Atom Has the Same Ability to Hold onto Its Own Electron, if It Needs Another Electron It Will "Share"

   3. H-H or H₂ Molecule

   4. H₂O Is a Covalent Compound that Has Molecules

   5. CH₄ Is a Covalent Compound that Has Molecules

9. Water
   1. The Universal Solvent

   2. The "Hydrogen Bond" Keeps Water Molecules Together

   3. Surface Tension

   4. Capillarity

   5. Phase Changes

   6. 4^oC

10. Carbon Dioxide
    1. CO₂

    2. H₂O + CO₂ ---> H₂CO₃

    3. Carbon Dioxide in Water Becomes an Important Buffer

    4. H₂CO₃ ---> H¹⁺ + HCO₃^1-

    5. The HCO₃^1- or Bicarbonate Ion Can Either Release H¹⁺ and Act as an Acid OR Take on H¹⁺ and Act as a Base

11. Acids, Bases and pH
    1. More H+ than OH- Then the pH 1 to 7

    2. Equal H+ and OH- Then the pH = 7

    3. More OH- than H+ Then the pH 7 to 14

    4. pH = Negative log of the H¹⁺ Concentration

    5. pH = - log [H¹⁺]