Lesson 2: Atomic Structure and Nuclear Energy


  • You will review the structure of atoms and molecules.
  • You will explore the law of conservation of mass.
  • You will examine a periodic table.
  • You will describe how energy is generated through nuclear reactions.

Time to Complete

60 minutes


For this lesson, you will be revisiting what you have learned about the atom, the periodic table, and the Law of Conservation of Mass.

  1. Complete the first column of the chart below by filling in what you know about the terms listed.

  1. Watch this video, “Just How Small is an Atom?” Complete the second column of the chart above with information you learned in the video.

Upload the document when you have finished.

Now that you’ve reviewed exactly what an atom is, it’s important to know that there are many types of atoms. In fact, there are more than 100 different atoms that have been identified so far. When a bunch of the same kind of atom are combined, it becomes an element.

A Russian chemist named Dmitri Mendeleev made a chart of all of the elements that had been discovered and that he believed would be discovered in 1869.  He called this chart the periodic table of elements.

  1. Watch this video about the periodic table of elements and use the Notes tool to answer the questions below.
  • What is the atomic number based on in the periodic table?
  • How is the periodic table supposed to be read?

Scientists have learned many things about atoms and elements over the years. An important term that is used when discussing atoms and elements is matter. Matter is defined as anything that has mass and takes up space. Matter is everything around us. Matter makes up atoms.

So, what is mass? Well, mass is the amount of matter in something. Mass is not the same as size, because smaller things can have more mass than larger things. For example, a baseball has more mass than a balloon filled with air even though the balloon is larger.

  1. Watch this video about the law of conservation of mass to learn more about the idea that mass can be neither created nor destroyed, it can only be rearranged.
  1. In the Notes tool, answer the following questions: What is the theory presented in the video about where atoms first came from since the law of conservation of mass says that mass can neither be created nor destroyed?

Let’s Get Started

As you’ve seen in the videos, energy is key. Energy can come in different forms, and it can be very powerful. Now, let’s consider what all of this has to do with power.

For a very long time, there was an accepted belief that atoms could not be broken apart. This all changed in 1938 when two German scientists, Otto Hahn and Fritz Strassmann, split uranium atoms into two or more parts. This discovery generated energy and lead to a revolutionary type of power known as nuclear fission.

  1. Watch the video, What is Nuclear Fission?
  1. Based on what you learned in the video, what are the positive and negative consequences of the development of nuclear fission? Answer in the Notes tool.

Let’s Get to Work

Energy generated from nuclear fission has both benefits and costs, and has become a very controversial topic over the years.

  1. Watch the video, Nuclear 101.
  1. If you are working on your own, consider partnering with a classmate over Zoom, Skype, or whatever distance learning collaboration tool your school has adopted.
  2. Identify the pros and cons of nuclear energy as is presented in the video, and makes notes in the Notes tool.

Let’s Wrap Up

  1. Now that you are more informed about the science of nuclear energy, use the Notes tool to write another opinion statement on your views of nuclear energy.

Be sure to upload all of your completed PDFs before moving on to your next lesson.