If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content

Unit 2: Chemistry of life

About this unit

This unit is part of the Biology library. Browse videos, articles, and exercises by topic.
Learn what matter is made of! We'll cover elements, atoms, and subatomic particles (protons, neutrons, and electrons). We'll also check out isotopes, radioactivity, and carbon dating.
Learn how electrons are organized in atoms! We will cover the Bohr model, electron shells, and orbitals, as well as periodic table trends in electron configurations and reactivity.
Find out how atoms interact with each other to form bonds! We'll look at the different types of strong bonds, including nonpolar covalent, polar covalent, and ionic bonds, as well as weak bonds such as hydrogen bonds and London dispersion forces.
Biology is brought to you with support from the Amgen Foundation