# Lesson 6: The Recurring (Periodic) Table of Elements

## Getting Started

One effective way to identity and to classify objects is by their function. For example, if I say "ball," there are a lot of ways to interpret that. If I say "a ball used for throwing sports," that is more specific. The function of the ball in a throwing sport eliminates some sports while including others. If I go on to say "a ball used in a popular North American throwing sport," football comes to mind. The throwing clue helps me classify which balls are the right ones to put in the group that I am developing. Another obvious sport is baseball. Although both balls are different, they are involved in sports that utilize throwing. There are also many other ways to classify any number of objects. The same can be said of classifying elements.

Classification systems are artificial. They do not neatly present themselves in the natural world, but all matter in the natural world has traits that make classification possible. One of the most famous classification systems is the periodic table of elements. The periodic table is a display of the chemical elements and is organized based on atomic numbers and electron configurations. Electron configuration is the distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals. Also utilized are chemical properties that are recurring or periodic. Elements are presented in order of increasing atomic number or number of protons and divided into three main groups: metals, nonmetals, and inert (or noble) gases.

In this lesson, the goal is to introduce you to the periodic table and to help you become familiar with how it is organized. As you proceed through the lesson, see if you can begin to make predictions based on the patterns found in the periodic table.

### Stuff You Need

• Eyewitness Chemistry by Ann Newmark
• periodic table of elements (kit)

• What makes one piece of matter different from another?
• What patterns can be observed in elements?

### Things to Know

• atomic mass: the mass of an atom
• electron configuration: the distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals
• metalloid: a nonmetallic element that has properties between those of a metal and nonmetal; some are also called semiconductors

### 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)
• Explain how the periodic table is a model for classifying elements and identifying the properties of elements. (S)
• Recognize the basis for the organization of the periodic table. (S)
• Know that the properties of the elements reflect the structure of atoms. (S)
• Know how to identify metals and nonmetals. (S)
• Know how to use the periodic table to identify elements. (S)

### Introducing the Lesson

On Day 1 of this lesson, your child will learn basic information about the organization of the periodic table including atomic number, atomic mass, number of protons, and number of electrons. She will also be challenged to complete a table that represents the electron configuration of different elements.

On Day 2, your child will be challenged to see patterns in the periodic table. She will be introduced to the different forms of the elements and be asked to complete a table based on certain patterns that she should be starting to recognize. Day 2 may be a brief activity and can be used to start reviewing for the test on this unit.