Lecture Notes: Introduction to Chemistry

Basics of Atoms

• Everything is made up of atoms.
• Atoms consist of:
  • Core: protons and neutrons.
  • Electrons.
• Different elements based on the number of protons.
• Quantum mechanics provides a more accurate depiction of atoms.

Atomic Structure

• Atoms have multiple electron shells.
• Valence electrons are in the outermost shell.
• Periodic Table:
  • Elements in the same column have the same number of valence electrons.
  • Group numbers indicate the number of valence electrons (except helium).
  • Transition metals do not follow a simple pattern.
  • Similar valence electrons lead to similar chemical behaviors.

Chemical Bonds

• Types of Chemical Bonds:
  • Covalent Bonds: Sharing of electrons for a full outer shell.
  • Ionic Bonds: Transfer of electrons, resulting in ions (cations and anions).
  • Metallic Bonds: Valence electrons are delocalized.
• Electronegativity influences bonding:
  • Increases from bottom left to top right of the periodic table.
  • Differences in electronegativity determine bond type.
• Intermolecular Forces (IMFs):
  • Hydrogen Bonds: Strong dipoles.
  • Van der Waals Forces: Temporary dipoles.

States of Matter

• Three main states: Solid, Liquid, Gas.
• Plasma as a high-temperature ionized gas.
• Temperature vs. Entropy:
  • Temperature: Average kinetic energy of particles.
  • Entropy: Amount of disorder.

Chemical Reactions

• Types: Synthesis, Decomposition, Single Replacement, Double Replacement.
• Stoichiometry: Ratios based on the conservation of mass.
• Physical vs. Chemical changes:
  • Chemical changes involve reactions and new substances.
• Activation Energy: Required to start a reaction.
• Catalysts lower activation energy.

Thermodynamics

• Enthalpy: Heat content of a system.
• Exothermic vs. Endothermic reactions.
• Gibbs Free Energy determines spontaneity of reactions.

Equilibrium and Acids-Bases

• Chemical Equilibrium: Reaction rates are equal in both directions.
• Acids and Bases:
  • Acids donate protons; bases accept protons.
  • pH scale measures acidity.

Redox Reactions

• Involve changes in oxidation numbers.
• Basic rules for determining oxidation states.

Quantum Mechanics and Electron Configuration

• Quantum Numbers: n, l, ml, ms define electron states.
• Electron Configuration follows the Aufbau principle.
• Valence electrons determine reactivity in metals and transition metals.

Conclusion

• The presented knowledge covers fundamental chemistry concepts.
• Encouragement for further engagement and learning.