flask Atomic Structure
Atomic structure explains the particles inside the atom and how electrons arrange themselves in shells and orbitals. These arrangements determine how every element behaves, so this topic unlocks the periodic table, bonding, and much more.
What you will learn
- Identify subatomic particles and their properties
- Use atomic number and mass number
- Explain isotopes and ions
- Write electron configurations
- Relate electron arrangement to chemical behavior
High School concepts
Atomic Number, Mass Number, and Notation
Atomic number defines the element, mass number counts nucleons, and nuclear notation packs both into one symbol.
Atomic Spectra and Electron Transitions
How electron transitions between energy levels produce emission and absorption spectra — each element's unique fingerprint.
Writing Electron Configurations
Writing electron configurations with the Aufbau principle, Pauli exclusion, Hund's rule, and noble-gas shorthand.
Electron Shells and Valence Electrons
Electron shells, subshells, and the valence electrons that control how atoms bond and react.
How Ions Form: Cations and Anions
How atoms gain or lose electrons to become cations and anions, and how to predict the charges they form.
Isotopes and Average Atomic Mass
What isotopes are, why they exist, how average atomic mass is computed, and how isotopes are used in dating and medicine.
The Periodic Table: Organization and Logic
How the periodic table is organized by atomic number and electron configuration — and why that organization predicts chemistry.
Subatomic Particles: Protons, Neutrons, Electrons
Protons, neutrons, and electrons: their charges, masses, locations, and how they define an atom's identity and behavior.