Unit 1: Atoms, compounds, and ions About this unit This unit is part of the Chemistry archive. Browse videos and articles by topic. For our most up-to-date, mastery-enabled courses, check …

Elements are pure substances with specific properties. Atoms are the smallest units of elements that still retain the element's properties. Atoms contain electrons, neutrons, and protons. Each …

Learn about elements and atoms in this Khan Academy video tutorial for AP Biology.

All matter is made up of substances called elements, which have specific chemical and physical properties and cannot be broken down into other substances through ordinary chemical …

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Well, an element doesn't always have the same number of neutrons in its atoms. Atoms of the same element with different numbers of neutrons are called isotopes.

We are now familiar with the building blocks of matter—elements and their atoms—and how they combine to form different types of substances like diatomic elements, molecular compounds, …

Atoms are the smallest units of matter that still retain the fundamental chemical properties of an element. Much of the study of chemistry, however, involves looking at what happens when …

Learn about atoms as the building blocks of elements, explore the periodic table as your guide to the elements, and understand how elements chemically combine to form compounds or …

Check your understanding of elements and atoms in this set of free, standards-aligned practice questions.