Comprehensive Study Notes on Atomic Structure and Theory

Atom

The smallest unit of matter that retains the properties of an element.

Nucleus

The positively charged center of an atom, containing protons and neutrons.

Proton

A positively charged subatomic particle found in the nucleus of an atom.

Neutron

A neutral subatomic particle located in the nucleus of an atom, contributing to its mass.

Electron

A negatively charged subatomic particle that orbits the nucleus of an atom.

Atomic number

The number of protons in the nucleus of an atom, determining an element's identity.

Mass number

The total number of protons and neutrons in an atom's nucleus.

Isotope

Atoms of the same element with the same number of protons but different numbers of neutrons.

Dalton's Atomic Theory

An early theory proposing that matter is made of atoms, which are indivisible and indestructible.

Quantum Mechanical Model

A theory that describes the behavior of electrons in atoms as wave functions rather than precise locations.