Decoding the Atom

Electron Cloud

The region where electrons orbit the nucleus

Atomic Orbitals

Three-dimensional regions where electrons are most likely to be found

Electron

A negatively charged subatomic particle that orbits the nucleus

Neutron

A neutral particle in the atomic nucleus

Atomic Nucleus

Positively charged center of the atom containing protons and neutrons

Proton

Positively charged particle in the atomic nucleus

Ground state

Lowest energy level, closest to the nucleus

Excited state

High and unstable energy level, farther from the nucleus

Orbitals

Clouds of probability within an energy level where an electron might be found

Aufbau Principle

Electrons fill orbitals starting with the lowest energy level and moving upwards

Pauli Principle

No two electrons can fill one orbital with the same spin

Hund’s Rule

Electrons fill each orbital singly before any orbital gets a second electron

Valence shell

Outermost shell of an atom

Valence electrons

Electrons that interact most with other atoms

Nonmetals

Receive electrons and become anions

Metals

Give away electrons and become cations