# Lesson 2: Atomic Structure

## Getting Started

In the first lesson, you were briefly introduced to the concept of structure and function. In this lesson you will take a closer look at atomic structure by developing an atomic model. The atomic model is a representation of the structure of an atom. By building a basic model, you will learn more specific details about the particles that make up the atom: the electron, the proton, and the neutron. The electron is a negatively charged particle with a small mass — it is found in all matter. It orbits the center, or nucleus, of the atom. The neutron is a particle that has zero electrical charge (also called a neutral charge) and a mass approximately equal to that of a proton. A proton is a particle that is a component of all atoms and carries a positive charge equal to that of the electron's negative charge. The nucleus (plural = nuclei) is the positively charged central region of an atom that consists of protons and neutrons. The nucleus contains most of the mass of the atom.

This lesson has three parts. The first two introduce you to the basics of atomic structure. The third part is a quick historical investigation that will give you insight into how scientists discovered that the atom was indivisible. During this lesson, keep in mind that all matter is made up of atoms or combinations of different atoms.

### Stuff You Need

• blank paper
• compass (kit)
• construction paper (kit)
• glue stick
• hole punch
• ruler
• scissors

• How do we know that atoms are made up of different parts?
• What is the importance of each part of the atom?
• How do these "same parts" make so many different elements?

### Things to Know

• atomic model: a representation of the structure of an atom
• nucleus: the positively charged central region of an atom, consisting of protons and neutrons and containing most of the mass of the atom
• electron: a negatively charged particle with a small mass that is found in all matter; orbits the nucleus of an atom
• neutron: a neutral particle with a mass approximately equal to that of a proton
• neutral: having no charge
• proton: a particle that is a component of all atomic nuclei and carries a positive charge equal to that of the electron's negative charge

### Skills

• Understand the structure, classifications, and physical properties of matter. (S)
• Recognize that all matter is made up of atoms. (S)
• Know that atoms of the same element are all alike but are different from the atoms of other elements. (S)
• Be able to describe the structure and parts of an atom and identify the properties of an atom including mass and electrical charge. (S)

### Introducing the Lesson

This lesson will take two days because it covers the history of atomic models and also asks your child to produce a basic atomic model. The order of the lesson works to give your child a frame of reference to consider. The lesson is self-inclusive and doesn't rely on information from Lesson 1, although it is possible that your child may make some connections between the lessons.

On Day 1 your child will create models of fluorine and sodium atoms and compare the two. On Day 2 he will create a timeline about important scientific discoveries related to the atom.