Chemistry Class - Subatomic Particles - Homeschool Science Chemistry

This is the third lesson in the homeschool science Chemistry Class I am putting together for elementary and middle school aged students! Today's topic is The Periodic Table and a reinforcement/review of Atomic Structure! Click HERE to see all the other lessons too!

If yesterday was your kid's first exposure to protons, neutrons, and electrons, and using the periodic table to calculate how many are in an atom, it will be very important to review those skills today! We're also going to include a little more information about the Periodic Table.


* Optional: Atomic Structure Printout
* Optional: Edible Atoms Printout
* Periodic Table
* Optional, but recommended: Computer or tablet with internet connection

At the end of this lesson, students will be able to...
1- Explain what an atom is.
2- List the 3 subatomic particles and the charge each of them have.
3- List the number of protons, neutrons, and electrons of any atom they can find on the Periodic Table.
4- Identify how many electrons are in the first 3 energy levels of an atom.
5- Explain why the periodic table is set up the way it is.


Read or Discuss: 
Let's look closer at the Periodic Table. Chemists started really trying to identify all the different elements they could find on Earth in the 1700's. By 1869, we knew of 63. Dmitri Mendeleev was a Russian chemist who was frustrated by the lack of organization of the elements. He decided he would create a system to organize them! He made 63 little cards, one for each known element at the time, and carried them with him everywhere! He constantly tried to find ways to organize them. Here is a picture of Dmitri:

At one point he worked for 3 days straight, then fell asleep and dreamed about his cards. He later said he had a dream where the cards lined up in a table, so when he woke up he quickly wrote down what he had seen. He moved a few elements around a bit after that, but he kept this basic pattern.

What was the pattern? The elements go in order, from the smallest atomic number (or number of protons) to the largest. Dmitri didn't know about atomic numbers at the time, but he knew the atoms' weights and he could see patterns in how they behaved.

Since he only had 63 elements to work with, he left holes in his chart where he predicted new elements would be discovered with properties that would make them fit the holes--like pieces in a puzzle!  As more than 100 years have gone by, we have now discovered more than 115 elements, and they all fit into Mendeleev's table!

We can use the patterns to learn about the elements too!  Look at each row, or "period." The period tells you how many energy levels those atoms need. So, atoms in the first period, hydrogen and helium, need one energy level for their electrons. Atoms in the second period need two energy levels for their electrons. Atoms in the third period need three energy levels for their electrons, and so on.

Elements in the same column (also called family or group) behave similarly. Elements in the first group (Group 1) all have one lone electron. These elements tend to combine with elements in Group 17, which all have room for one more electron. Elements in Group 18 are all very stable and tend not to react.

The non-metals (except for hydrogen) are all on the right hand side of the periodic table. The heaviest elements tend to break down into smaller elements quickly, releasing radioactive energy. These are found at the bottom of the periodic table.

Let's review what is inside of an atom!

Pick any element on the Periodic Table, and calculate how many protons, neutrons, and electrons are in that atom. Remember that the atomic number (the smaller one in the square) is the number of protons and electrons. The atomic weight (the bigger number in the square) is the combination of protons plus neutrons. To find the number of neutrons, round the atomic weight to the nearest whole number, and then subtract the number of protons. 

Protons = the atomic number
Electrons = the atomic number (if your atom has a neutral charge)
Neutrons = (the atomic weight) - (the # of protons)

Then choose one of the following three ways to practice that calculation:

1- Recommended: Use the virtual labs available at to experiment with changing the subatomic particles for at least 5-10 minutes. Then play a few rounds of the game. 

2- Make a list of 5-10 atoms and the numbers of protons, neutrons, and electrons in each one.

3- Repeat the lab from yesterday with 5 different elements.

Review/Final Discussion:

1- What is an atom?
2- What are 3 subatomic particles? What charge does each particle have?
3- How many electrons can fit in an atom's first energy level? Second? Third?
4- How many protons are in calcium? What is calcium's atomic number? How many neutrons are in calcium? How many electrons? How many energy levels does calcium need for its electrons?


This is the third lesson in my Atoms & Molecules Chemistry Class for homeschoolers!  Click HERE to get the rest!

And if you're looking for more homeschool unit studies, be sure to check out our growing collection here!

Happy Educating,
Carla & the kids who don't sit still!



  1. What a fun chemistry lesson! I especially love your method for practicing equations! ~Amy @ Orison Orchards