Chemistry
Understand the composition, structure, and reactions of matter. From atoms and bonding to stoichiometry and solutions, build the skills to analyze and predict chemical behavior.
Popular Topics
Atomic Structure
Atoms consist of protons and neutrons (nucleus) and electrons (electron cloud).
Interactive Periodic Table
The periodic table arranges all known elements by atomic number, electron configuration, and recurring chemical properties.
Mole Concept
The mole is a counting unit: 1 mol = 6.022 × 10²³ particles (Avogadro's number).
Stoichiometry
Stoichiometry uses balanced equations to calculate amounts of reactants and products.
1Atomic Structure & Bonding
Atomic Structure
Atoms consist of protons and neutrons (nucleus) and electrons (electron cloud).
Electron Configuration
Electron configuration describes how electrons are distributed among orbitals in an atom.
Periodic Trends
The periodic table organizes elements by increasing atomic number.
Interactive Periodic Table
The periodic table arranges all known elements by atomic number, electron configuration, and recurring chemical properties.
Ionic vs Covalent Bonding
Ionic bonds form when electrons are transferred from a metal to a nonmetal.
Lewis Structures
Lewis structures show valence electrons as dots and bonding pairs as lines.
Balancing Chemical Equations
A balanced equation has equal numbers of each atom on both sides.
2Quantitative Chemistry & Solutions
Mole Concept
The mole is a counting unit: 1 mol = 6.022 × 10²³ particles (Avogadro's number).
Stoichiometry
Stoichiometry uses balanced equations to calculate amounts of reactants and products.
Gas Laws
Boyle's Law: P₁V₁ = P₂V₂ (constant T).
Solutions & Concentration
A solution consists of a solute dissolved in a solvent.
Acids & Bases
Acids donate H⁺ (protons); bases accept H⁺ (Brønsted-Lowry definition).