CHEM 201: Atomic and Ionic Bonding, Nomenclature, and Composition of Compounds

CHEM 201 Study Notes: Atomic and Ionic Bonding, Nomenclature, and Composition of Compounds

I. Basic Structure of Atoms

  • Composition of Atoms
    • Atoms consist of three subatomic particles: protons, neutrons, and electrons.
    • Protons and neutrons are located in the nucleus of the atom.
    • Electrons are situated in regions outside the nucleus.
  • Atomic Number
    • The atomic number of an element is defined as the number of protons in its nucleus.
  • Empty Space
    • Atoms are primarily comprised of empty space, which signifies that the density of atoms is predominantly concentrated in the nucleus.

II. Behavior of Light and Electrons

  • Properties of Light
    • Light exhibits both wave-like and particle-like properties.
    • The particle aspect of light is termed photons.
  • Photon Energy
    • Photons possess quantized energy, signifying that they can only exist at specific energy levels.
  • Electron Configuration
    • Electrons exist in discrete, quantized energy levels around the nucleus.
    • Electrons fill sublevels starting from the lowest energy level and proceeding to higher ones sequentially.

III. The Periodic Table

  • Arrangement of Elements
    • Elements in the periodic table are organized by increasing atomic number.
    • Elements display regular, repeating chemical and physical properties.
    • Groups/Families: Vertical columns in the periodic table.
    • Periods/Series: Horizontal rows in the periodic table.

IV. Trends in the Periodic Table

  • Atomic Radius and Metallic Character
    • Both decrease from left to right across a period and from bottom to top in a group.
    • Example: The smallest anion is Fluoride (F-).
  • Energy Levels
    • The periodic table is divided into blocks based on the filling of specific sublevels.

V. Valence Electrons and Ionization Energy

  • Valence Electrons
    • These are the outermost electrons of an atom and are active in chemical reactions.
  • Ionization Energy
    • Defined as the energy required to remove an electron from an atom in the gaseous phase.

VI. Predicting Ionic Charges

  • The charge on an ion can often be predicted by its position in the periodic table, particularly for main group elements.

VII. Types of Compounds

  • Inorganic Compounds
    • Most inorganic compounds do not contain carbon.
  • Types of Ionic Compounds
    • Binary Ionic Compounds: Composed of a metal and a nonmetal.
    • Ternary Ionic Compounds: Composed of a metal, a nonmetal, and oxygen.
  • Acids
    • Composed of hydrogen along with either a nonmetal or an oxyanion.

VIII. Nomenclature of Ionic Compounds

  • Naming Cations
    • Cations are named by adding the word "ion" to the element's name.
    • For cations with multiple possible charges, the charge is indicated using Roman numerals (e.g., Iron(II) ion).
  • Naming Ionic Compounds
    • The naming structure is as follows: cation named first followed by anion with the suffix –ide.
    • The simplest representative unit for an ionic compound is termed a formula unit.

IX. Acids Naming Rules

  • Binary Acids
    • These are named by prefixing "hydro" to the nonmetal stem and adding "–ic acid" (for instance, HCl is hydrochloric acid).
  • Ternary Oxyacids
    • Named by modifying the suffix of the oxyanion: –ate to –ic acid and –ite to –ous acid.

X. Tables of Common Ions

  • Invariant Cation Charges
    • Some metals maintain a consistent charge, which can be found in a tabular format (e.g., Lithium $ ext{Li}^+$, Sodium $ ext{Na}^+$).
  • Cations with Multiple Charges (Type II Cations)
    • These can include metals such as Iron that can form ions with different charges (e.g., Iron(II) $ ext{Fe}^{2+}$ and Iron(III) $ ext{Fe}^{3+}$).
  • Common Polyatomic Ions
    • Examples: Ammonium $ ext{NH}4^+$, Nitrate $ ext{NO}3^–$, Sulfate $ ext{SO}_4^{2–}$.

XI. Practice Exercises and Examples

  1. Classifying Compounds and Acids

    • Example Classification:
      • Calcium oxide, $ ext{CaO}$: binary ionic compound.
      • Sulfur dioxide, $ ext{SO}_2$: binary molecular compound.
      • Silver chromate, $ ext{Ag}2 ext{CrO}4$: ternary ionic compound.
      • Hydrofluoric acid, $ ext{HF(aq)}$: binary acid.
      • Carbonic acid, $ ext{H}2 ext{CO}3(aq)$: ternary oxyacid.

  2. Applicable Formulas

    • For binary ionic compounds, balance the charges to predict the resultant formulas based on the charges of constituent ions.
    • Example: Copper(I) oxide, $ ext{Cu}_2 ext{O}$ from $ ext{Cu}^{+}$ and $ ext{O}^{2-}$.

XII. Trends in Ionization Energy

  • Ionization energy increases as one moves up a group and from left to right across a period.

XIII. Electron Configurations and Quantum Numbers

  • Electron Configurations
    • Example: For Phosphorus (P), the configuration is $1s^2 2s^2 2p^6 3s^2 3p^3$.
  • Quantum Numbers
    • Specify the properties of orbitals (n, l, and m) and their permissible values.

XIV. Implications of Electron Configurations

  • Understanding electron configurations helps predict reactivity and chemical bonding behavior of elements.

XV. Example Exercises on Calculation of Energy and Frequency

  • Energy Calculation
    • The energy of a photon can be calculated using $E = hv$, where $h$ is Planck's constant and $v$ is the frequency.
    • The calculation of frequency from wavelength utilizes the relationship $λv = c$, where $c$ is the speed of light.

XVI. Assessments and Practice Questions

  • Regular practice through problem sets and exercises to reinforce understanding of atomic structure, periodic trends, nomenclature, and compound classification.

XVII. Review Questions

  • Multiple-choice questions on chemical naming, classification of compounds, and prediction of formulas to gauge understanding of nomenclature and chemical behavior.