Molecules, crystals, and diatomic elements | Middle school chemistry | Khan Academy

Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now: https://www.khanacademy.org/science/m... Want to explore more? Check out the full middle school playlist here:    • Middle school chemistry | Khan Academy   Elements and compounds can exist as pure substances, each with a fixed, definite composition. Some compounds, like water, are made of individual molecules. Others, like salt, form crystals—large, repeating 3D patterns without individual molecules. Additionally, some elements pair up as diatomic molecules, such as O₂ and H₂, rather than existing as single atoms. Understanding whether a substance is molecular or crystalline and how diatomic elements differ from compounds is key to classifying matter. 00:00 Intro 00:48 What are crystals? 01:50 Chemical formula of crystals 03:29 General types of compounds 04:03 Diatomic elements 05:11 Summary of pure substances Khan Academy is a nonprofit organization with the mission of providing a free, world-class education for anyone, anywhere. We offer quizzes, questions, instructional videos, and articles on a range of academic subjects, including math, biology, chemistry, physics, history, economics, finance, grammar, preschool learning, and more. We provide teachers with tools and data so they can help their students develop the skills, habits, and mindsets for success in school and beyond. Khan Academy has been translated into dozens of languages, and 15 million people around the globe learn on Khan Academy every month. As a 501(c)(3) nonprofit organization, we would love your help! Donate or volunteer today! Donate here: https://donate.khanacademy.org/give/4... Volunteer here: https://www.khanacademy.org/contribut...