Atoms, Elements, Periodic Table

The atomic number tells us the number of protons in an atom.

Most of an atom's mass is found in the nucleus.

The smallest piece of an element is called an atom.

No, not all elements occur naturally on Earth.

A valence electron is an electron that is farthest from the nucleus.

An atom is made of protons, neutrons, and electrons.

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

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

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

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