Cellular Chemistry

Lesson Plan - Get It!

Audio:

• What do you already know about chemistry?

Chemistry has many different kinds of interactions. This lesson explores the foundation of chemistry.

Important vocabulary words will be italicized. Keep track of them all in your science notebook.

Be sure to include the term and its meaning like this example.

Currently (2023), there are 118 known elements, and they are organized on the periodic table.

These elements are each unique because they have a specific number of protons. Protons are tiny atomic particles with a positive charge.

You can tell how many protons each element has by looking at the number above its symbol in the periodic table.

For example, the first element on the table, hydrogen, has the symbol H and the number 1 above it. That means it has 1 proton.

Go down to the bottom of the same column and find francium, which has the symbol Fr.

• How many protons does francium have?

Elements also have electrons, atomic particles with a negative charge, and neutrons, particles with no charge. It's easy to tell the number of electrons an element has because it's the same as the number of protons.

For example, hydrogen has 1 proton and 1 electron, while francium has 87 protons and 87 electrons.

• But what about neutrons?

You have to do some subtraction to figure that out. Under each element's symbol is another number called the atomic mass.

It's hard to see it in the image above, so take a look at this dynamic Periodic Table.

If you click on francium, you'll see its atomic mass is 223. That number is the sum of the protons and neutrons. All you have to do is subtract the number of francium's protons (87) from its atomic number, 223, and you get 136.

If the atomic mass is a decimal, like 50.9, round up to the nearest whole number, 50.

Write down some notes now on how to find the number of protons, electrons, and neutrons in an element.

You'll need that information for the quiz in the next section.

Atoms

Take a closer look at an atom. Below are two diagrams showing a carbon atom.

You can see that the electrons (marked E) orbit around the nucleus, which is composed of protons (P) and neutrons (N). In the second diagram, you can see how the electrons move in an elliptical orbit and that some are closer to the nucleus while others are farther away.

Metals, Nonmetals, and Metalloids

Looking closely, you'll notice something else about the periodic table.

The periodic table is divided into three main groups — metals, nonmetals, and metalloids — based on the arrangement of protons, electrons, and neutrons.

In the image above, metals are shown with a blue color. Metals are usually solid at room temperature and can conduct electricity and heat.

Think about what happens to a metal spoon left on a hot stove! Ouch! Metals can be manipulated — you can pull them into wire or hammer them into sheets like aluminum foil.

Nonmetals are shown in the image above in a yellow color. Nonmetals can be gases, liquids, or solids. Oxygen is a gas at room temperature, but phosphorus is solid.

These elements do not conduct electricity and are much harder to manipulate. The atoms are usually farther apart, making changing the shape or structure harder.

Metalloids are a special group, shown in pink. These elements have some characteristics of metals but some of nonmetals. They can be any phase — solid, liquid, or gas — at room temperature.

Depending on its development, silicon can conduct electricity or insulate substances. They have an extensive range of uses!

Scientists use the periodic table to organize elements and identify unknown substances based on characteristics and atomic structure.

• Based on what you have learned, how do you think the periodic table and life science are related?
• How are metals and nonmetals different?
• Why do you think we use metals in many technological products?
• What role do you think electrons play in the ability to conduct electricity?

• Ready to practice chemistry basics?

Move to the Got It? section to review the terms from this section.