Atomic Structure and Theory

The atomic number is the number of protons in the nucleus of an atom, which determines the element's identity.

Protons are positively charged subatomic particles found in the nucleus of an atom.

Neutrons are neutral subatomic particles found in the nucleus of an atom.

Electrons are negatively charged subatomic particles that orbit the nucleus of an atom.

The mass number is the total number of protons and neutrons in the nucleus of an atom.

Isotopes are variants of the same element that have the same number of protons but different numbers of neutrons.

The standard unit of atomic mass is the atomic mass unit (amu).

To calculate the number of neutrons, subtract the atomic number from the mass number.

The nucleus is the central part of an atom, containing protons and neutrons.

A proton has a positive charge.