Lesson Plan - Get It!
- What is that little zap you get when you touch a metal doorknob in dry weather?
- What is lightning?
- How do elements combine to make different substances?
Enough questions! Read on for answers!
- Did you know that electricity is just a beam of charged particles?
These particles are called electrons, and they carry a negative charge. In the previous Atoms Related Lesson, you learned that neutrons are found in the nucleus of an atom alongside protons. Electrons are not found in the nucleus, but in a cloud that surrounds the dense positive core.
If you missed or need to review the first Atoms Related Lesson on protons, find it in the right-hand sidebar.
Electrons move quickly around the nucleus, and are much smaller than protons or neutrons. That is why we don't include the mass of electrons in the atomic mass of an element.
In the image above, you can see the rings holding their electrons; these are called shells. The electrons surrounding a nucleus are organized into different layers, but are constantly bouncing back and forth. This movement makes it impossible to know exactly where an electron is in the atom at any given time.
The number of shells that an atom has depends on how many electrons an atom holds. The more electrons, the more shells are needed to house the negative particles. For example, Molybdenum has five shells to fit all 42 of its electrons!
Electrons allow atoms to bond together. When two atoms bond, electrons are either shared between two nuclei or transferred.
In covalent bonding, the electrons are shared due to the type of atoms involved in the bond. This bond allows the atoms to fill the outer shell, providing a more stable atomic structure for both atoms in the bond.
Notice how electrons are shared between atoms of carbon and oxygen in the outer shells. That allows each atom to be more stable.
In ionic bonds, electrons are transferred from one atom to another. This process also increases the stability in each atom, and occurs between metals and nonmetals.
Notice how the electron moves from the sodium to the chlorine atom below. When the sodium atom loses that electron, it becomes positively charged, while the chlorine atom becomes negatively charged due to the extra electron.
Chemical bonding allows interactions that drive the world around us! Without electrons to bond atoms, we wouldn't have water, carbon dioxide, or sugar!
To review, electrons are the negatively-charged particles found in atoms. They are very small and are not included in the mass of the atom. They move quickly through shells surrounding the nucleus, which allows them to bond with other atoms.
- What do you think would happen to an atom if it gained or lost electrons?
- How might that change the atomic structure?
Summarize what you have learned about electrons by creating a picture that includes major ideas from this section of the lesson.
In the Got It? section, you will learn more about the discovery of the electron.