Basics of Chemistry

Atoms and Their Structure

• Atoms: Fundamental building blocks of matter.
• Components of Atoms: Consist of a core (protons and neutrons) and electrons.
• Elements: Defined by the number of protons.
• Valence Electrons: Electrons in the outermost shell.

Periodic Table

• Groups: Columns with elements having the same number of valence electrons.
• Periods: Rows where elements have the same number of shells.
• Three Categories: Metals (left), Non-metals (right), Semimetals (line in between).

Types of Bonds

• Covalent Bonds: Sharing of electrons, strength depends on electronegativity.
• Ionic Bonds: Transfer of electrons (e.g., Sodium Chloride).
• Metallic Bonds: Free-moving valence electrons in a metal grid.
• Intermolecular Forces (IMFs): Include hydrogen bonds, Van der Waals forces.

Properties and Reactions

• States of Matter: Solid, liquid, gas (and plasma at high energy).
• Temperature and Entropy: Impact state transitions and reaction spontaneity.
• Chemical Reactions: Include synthesis, decomposition, single replacement, and double replacement; Guided by stoichiometry and conservation of mass.
• Activation Energy: Required to initiate reactions; catalysts lower this energy.
• Energy Changes: Exothermic (heat released) vs. endothermic (heat absorbed).
• Gibbs Free Energy: Determines spontaneity of reactions involving enthalpy and entropy.

Acids, Bases, and pH

• Bronsted-Lowry Definition: Acids donate protons, bases accept protons.
• pH Scale: Measures acidity/basicity; pH + pOH = 14.
• Neutralization: Reaction between strong acid and strong base to form water and a salt.

Redox Reactions

• Oxidation and Reduction: Transfer of electrons; Oxidation numbers help track electron flow.
• Balancing Equations: Ensuring mass and charge balance in reactions.

Quantum Mechanics and Electrons

• Quantum Numbers: Describe electrons in terms of shells (n), subshells (l), orbitals (ml), and spin (ms).
• Electron Configuration: Described by the Aufbau Principle; relates to element's position on periodic table and valence electrons.

Mixtures and Solutions

• Types of Mixtures: Homogeneous (uniform) vs. Heterogeneous (non-uniform).
• Colloids and Suspensions: Intermediate types with particles not fully dissolved.