Basic Concepts of Atomic Structure

Front

Atom

Back

The basic unit of matter and the defining structure of elements.

Front

Subatomic Particle

Back

Particles smaller than an atom (protons, neutrons, electrons).

Front

Proton (p⁺)

Back

Positively charged particle in the nucleus; determines atomic number.

Front

Neutron (n⁰)

Back

Neutral particle in the nucleus; contributes to atomic mass.

Front

Electron (e⁻)

Back

Negatively charged particle in electron shells orbiting the nucleus.

Front

Nucleus

Back

Dense, positively charged center of the atom containing protons and neutrons.

Front

Quark

Back

Sub-particle that makes up protons and neutrons.

Front

Lepton

Back

Family of particles that includes electrons.

Front

Atomic Number (Z)

Back

Number of protons in the nucleus; also equals electrons in a neutral atom.

Front

Atomic Mass (A) / Mass Number

Back

Total number of protons + neutrons in the nucleus.