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

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

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