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The elements listed in the periodic table are the "building blocks" of the substances that make up our world. Because there are over one hundred elements, there are many different ways those elements can be combined to make all the various compounds that surround us. In this activity, you will learn how chemical compounds are named.

In the previous lesson, you learned how matter is organized in the periodic table based on its symbol, atomic number, and atomic mass. For example, the element below, oxygen (element name), has a chemical symbol of "O," an atomic number of 8 (the number of protons in the nucleus), and an atomic mass of 15.999 (the number of protons/electrons and neutrons).

Sometimes elements combine in nature to create a compound, and sometimes the combinations are man-made. Compounds can be written down using a chemical formula, which is a shorthand way to represent them. A chemical formula tells us the number of atoms of each element in a compound.

So what exactly is a chemical compound? A compound is a pure substance composed of two or more different chemical elements. Compounds can only be separated by a chemical reaction.

Let's take a look at a couple of examples.

Water
Formula: H2O = 2 hydrogen (H) + oxygen (O)

When no numbers are in the chemical formula for a compound, there is an equal number of each element in the compound. For example, salt has the chemical formula NaCl. This means each molecule of salt is made up of one atom of sodium (Na) and one atom of chlorine (Cl).

Salt

Formula: NaCl = sodium (Na) + chlorine (Cl)

Below is a list of some common chemical compounds. The chart shows the compound name, the elements that combine to make the compound, and the chemical formula. You will learn more about chemical formulas in the next activity.

Click on the Play button below to watch a video on chemical compounds.

Click here to go to an interactive periodic table. Click on two or more of the elements to show all of the compounds that contain those elements.

Self-Check

Try This!

Click here to go to the Study Jams! website to watch a video. When you have finished watching the video, click on the "close" button in the upper right-hand corner to exit the video. Then, click on the "Test Yourself" button to see how much you know about elements and compounds.

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