Lecture Notes: Introduction to Basic Chemistry

Atomic Structure

• Atoms: Building blocks of matter.
  • Composed of a nucleus (protons and neutrons) and electrons.
• Elements: Different elements have different numbers of protons.
  • Example: Water is made of hydrogen and oxygen.

Quantum Mechanics and Electron Shells

• Electron Shells: Atoms have multiple shells.
  • Valence Electrons: Electrons in the outermost shell.
  • Chemistry often involves the behaviors of these electrons.

The Periodic Table

• Groups and Periods:
  • Elements in the same group have the same number of valence electrons.
  • Elements in the same period have the same number of electron shells.
• Periodic Table Layout:
  • Metals on the left, non-metals on the right, semimetals on the line.

Bonding and Interactions

• Ions: Atoms with unequal numbers of protons and electrons.
  • Cations (+), Anions (-).
• Types of Bonds:
  • Covalent Bond: Sharing of electrons.
  • Ionic Bond: Transfer of electrons.
  • Metallic Bond: Delocalized electrons in metals.
  • Hydrogen Bond: Special dipole interactions.
  • Van der Waals Forces: Temporary dipoles due to electron movement.
• Electronegativity: Measure of an atom's tendency to attract electrons.

States of Matter

• Solid, Liquid, Gas: Defined by particle arrangement and movement.
• Temperature and Entropy:
  • Temperature: Average kinetic energy.
  • Entropy: Measure of disorder.

Chemical Reactions and Stoichiometry

• Reaction Types:
  • Synthesis, Decomposition, Single Replacement, Double Replacement.
• Stoichiometry: Ratios in chemical reactions.
• Mole Concept: Allows measurement of specific numbers of atoms.
• Activation Energy and Catalysts:
  • Catalysts lower activation energy without being consumed.

Energy Changes in Reactions

• Exothermic vs Endothermic:
  • Exothermic: Releases energy.
  • Endothermic: Absorbs energy.
• Gibbs Free Energy: Determines spontaneity of reactions.

Acids and Bases

• pH Scale: Measures acidity or basicity based on hydronium ion concentration.
• Acid-Base Reactions: Involves transfer of protons.

Redox Reactions

• Oxidation and Reduction: Involves transfer of electrons.

Electron Configuration and Quantum Numbers

• Quantum Numbers: Describe electron properties and positions.
• Electron Configuration: Arrangement of electrons in atoms.
  • Aufbau Principle: Order electrons fill orbitals.

Conclusion

• The basics of chemistry revolve around atomic structure, bonding, reactions, and energy changes.
• Understanding these concepts provides insight into the physical and chemical properties of substances.