Atomic Structure Diagram
Free printable atomic structure diagram — a labeled Bohr model showing the nucleus with protons and neutrons, and electrons on their shells. Download a high-resolution PDF or PNG for Letter paper.
The parts of an atom
An atom is the tiny building block of all matter. This Bohr model shows its main parts: a central nucleus of protons and neutrons, orbited by electrons on their shells. Here is what happens at each labeled part of the diagram:
| Part | What it does |
|---|---|
| Nucleus | The dense center of the atom, made of protons and neutrons; it holds almost all of the atom's mass. |
| Proton | A positively charged particle in the nucleus. The number of protons decides which element the atom is. |
| Neutron | A particle in the nucleus with no electric charge. It adds mass and helps hold the nucleus together. |
| Electron | A tiny negatively charged particle that moves around the nucleus. |
| Electron shell | A path, or energy level, around the nucleus where electrons travel. Shells fill from the inside out. |
Companion worksheet
A free fill-in worksheet with an answer key, built from the labels above — students match each part to its description, then answer a couple of short questions. Great for a quick check after using the diagram.
How to print
Choose Download PDF for a ready-to-print file that fits US Letter paper (8.5 × 11") in landscape, or Download PNG for the high-resolution image.
Frequently asked questions
What are the three main parts of an atom?
Protons and neutrons in the central nucleus, and electrons that move around it on electron shells.
What is the Bohr model?
The Bohr model is a simple picture of the atom that shows electrons orbiting the nucleus on fixed shells, like planets around the sun. It is great for learning the basic parts of an atom.
What paper size should I print this on?
The diagram is sized for standard US Letter paper (8.5 × 11") in landscape orientation. Use "Download PDF" for a print-ready file that fits the page automatically.