This resource is the PhET Build an Atom Virtual Inquiry Lab. This resource includes: (1) Student Lab Handout, (2) Answer Key, and (3) Teacher Directions. Students will use the PhET website to access their online Build an Atom Lab. The PhET Build an Atom Lab Handout has Six Parts. Part 1: Discovery Subatomic Particle Charge Properties (Protons, Neutrons, Electrons, Atomic Number, Mass Number, Neutral Atom, Ions), Part 2: Summary of Subatomic Particle Properties (Fill Out Sentence Frames),