By Maya Austen – Updated Mar 24, 2022

An atom is the smallest unit of a chemical element that preserves its characteristic properties. It consists of a positively charged nucleus—made of protons and neutrons—and a cloud of negatively charged electrons that orbit the nucleus. Accurately diagramming an atom requires knowing the number of protons, neutrons, and electrons, as well as the element’s electron‑shell configuration.

Step 1 – Find the Element’s Basic Data

Consult a modern Periodic Table of Elements to locate the atomic number and atomic weight of the element you wish to illustrate. The table’s grid squares list these values; the atomic number appears at the top of each square, while the atomic weight is shown at the bottom. These figures are the foundation for all subsequent calculations.

Step 2 – Count Protons and Electrons

The atomic number equals the number of protons in the atom. Because neutral atoms have no net charge, the electron count is identical to the proton count. For instance, nitrogen (N) has an atomic number of 7, so a neutral nitrogen atom contains 7 protons and 7 electrons.

Step 3 – Determine the Neutron Count

Neutrons are calculated using the formula:
Mass Number – Protons = Neutrons

To obtain the mass number, round the atomic weight to the nearest whole number. Nitrogen’s atomic weight is 14.0067; rounded, the mass number is 14. Subtracting the 7 protons gives 14 – 7 = 7 neutrons.

Step 4 – Draw the Nucleus

Sketch a cluster of circles representing the nucleus. Use one circle for each proton and one for each neutron. Distinguish protons by adding a positive sign or coloring them differently, and leave neutron circles blank or color them uniformly. This cluster visually conveys the nucleus’s composition.

Step 5 – Identify the Electron‑Shell Configuration

Electron‑shell configuration lists how electrons occupy energy levels around the nucleus. For example, nitrogen’s configuration is 1s² 2s² 2p³, meaning two electrons in the first shell and five in the second. Understanding this arrangement is key to accurate diagramming.

Step 6 – Sketch the Electron Shells

Draw concentric rings around the nucleus, one for each shell indicated by the configuration. On each ring, place small circles representing the electrons in that shell—the first ring being the closest to the nucleus. This completes the visual representation of the atom.