Education Technology

Build an Atom (HS)

Updated on 10/04/2017

Activity Overview

In this lesson, students will simulate, observe, and manipulate the variables that affect the structure and, therefore, the properties of an atom.


  • Students will discover that atoms are made up of particles and that the number of particles in an atom affects its properties.
  • Students will learn that these particles - protons, neutrons, and electrons - are found in specific locations in the atom.
  • Students will learn that neutrons have a neutral charge, protons a positive charge (+), and electrons a negative (-) charge; atoms become unstable with large imbalances between the charges.
  • Students will learn that an atom is neutral when there is the same number of protons as electrons; the charge of the atom becomes either positive or negative, depending on the net gain of either electrons (-) or protons (+).
  • Students will learn about how atomic number, mass and net charge are determined.
  • Students will learn about the organization of the Periodic Table.


  • proton
  • neutron
  • electron
  • ion
  • net charge

About the Lesson

Adapted from a PhETTM simulation, lesson involves students manipulating an atom's composition and observing the change in atom identity, stability, overall charge, size, and atomic symbol

PhET is a trademark owned by the Regents of the University of Colorado, which was not involved in the production of, nor do they endorse this product.