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Elements and Compounds


Oxygen and nitrogen are examples of . An element is any substance that cannot be broken down into simpler substances. The smallest unit of an element is called an . An element is made up of only kind of atom. The elements found in living things include carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur.


Carbon dioxide is a made up of the elements carbon and oxygen. When two or more elements combine chemically, they form a . Most elements in living things occur in the form of compounds. The smallest unit of many compounds is called a . Water is another compound. Each water molecule is made up of hydrogen atoms and oxygen atom.

Organic and Inorganic Compounds

Many of the compounds found in living things contain the element . Most compounds that contain carbon are called compounds. Some important groups of organic compounds found in living things are carbohydrates, lipids, proteins, and nucleic acids. As you may know, many of these compounds are found in the foods you eat. This is not surprising, since the foods you eat come from living things. Compounds that don't contain the element carbon are called compounds. Water and sodium chloride, or table salt, are familiar examples of inorganic compounds. Organisms contain many inorganic compounds as well as organic compounds.

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