Calculating protons, neutrons, and electrons (Worksheet included)
Everything around us is composed of atoms. Therefore, atomic structure is an important concept for students to understand and master. However, chemistry is often viewed as abstract, boring, and difficult. It doesn’t have to be that way.
The following post breaks down the basics of parts of the atom, an overview of the periodic table of elements, and calculating protons, neutrons, and electrons. I’ll also provide you with a FREE Calculating protons, neutrons, and electrons worksheet.
Atomic Structure
All matter is made of atoms. Atoms of different elements bond to create the things that surround us (including every living thing and nonliving thing). Therefore, the basics of atomic structure are an important chemistry lesson.
An atom has three subatomic particles – protons, neutrons, and electrons. In the Bohr Model of an atom, the positively charged protons and neutral neutrons “live” in the nucleus of the atom.
Unlike the electrons that have a negative charge and travel around the outside of the nucleus in different energy levels (sometimes also referred to as shells).
Once students understand atomic structure, they are introduced to calculating protons, neutrons, and electrons by using the information found in the periodic table of elements.
As an overview:
Charges of Subatomic Particles
- Protons: Positively Charged
- Neutrons: Neutral (no) Charge
- Electrons: Negative Charge and
Location of Subatomic Particles
- Protons: Nucleus
- Neutrons: Nucleus
- Electrons: Electron Cloud (aka energy levels, orbitals, shell)
The Periodic Table of Elements
The periodic table of elements contains all the known elements in the universe. It is organized by atomic number (each element has its own unique atomic number).
In addition to the atomic number, the periodic table of elements also displays the atomic mass (also known as the mass number), element names, and symbols.
Knowing the atomic number and mass allows us to calculate the number of protons, neutrons, and electrons in an atom of an element.
Calculating the Protons, Neutrons, and Electrons
In reading the periodic table of elements, the atomic number tells us the number of protons as well as the number of electrons in an atom of the element (different elements have different numbers of protons and therefore, different atomic numbers).
For example, the periodic table tells us that the atomic number of Carbon is 6. Therefore, in an atom of Carbon, there are 6 protons and 6 electrons. To calculate the number of neutrons, one subtracts the atomic number from the atomic mass.
Let’s use Carbon as an example again. The atomic mass of Carbon is 12. The atomic number of Carbon is 6. Therefore, we subtract 6 from 12 (12-6) to get the number of neutrons.
In other words, the number of neutrons = The atomic mass – the atomic number. For Carbon: the number of neutrons = 12-6=6. Therefore there are 6 neutrons in an atom of Carbon.
# of Protons = Atomic Number
# of Electrons (in an atom) = Number of Protons = Atomic Number
# of Neutrons = Atomic Mass (mass number)- Number of Protons
Calculating Protons, Neutrons, and Electrons (Free Worksheet)
I created a free worksheet to help you teach students how to use the periodic table of elements to calculate the number of subatomic particles.
In this calculating protons, neutrons, and electrons worksheet, students begin by completing information about elements by looking at the periodic table of elements.
Next, students learn how to use that information to calculate the number of protons, neutrons, and electrons.
Finally, this free worksheet provides students with the chance to practice what they learned with atoms of the following elements: Aluminum, Lithium, Calcium, and Gold.
This free worksheet also comes with a teacher answer key as well as a FREE Google Slides deck for those of you who prefer digital worksheets.
And as always, Lit Science lessons are created with English Learners and developing readers and writers in mind. Therefore, the worksheets contain scaffolds with embedded images to assist in comprehension for English learners.
I’ve also embedded a scaffold that includes the formula for calculating the number of neutrons as described in this post.
Download this Calculating Protons, Neutrons, and Electrons Worksheet for FREE here. And if you’re looking for a great way to delve deeper into teaching about matter and the parts of an atom, I also have scaffolded lessons to provide access for all students. Shop now.
