What Are Chemical Elements

Everything in the universe is made from chemical elements. An element is a substance made of only one type of atom. Oxygen, gold, and carbon are all elements. There are about 118 known elements. They are organized in a chart called the periodic table.

What Makes an Element

Each element is made of atoms that have the same number of protons in their center. Hydrogen has 1 proton. Helium has 2. Carbon has 6. This number is what makes each element unique. Elements cannot be broken down into simpler substances by normal chemical reactions.

Elements Combine

Elements can combine with other elements to make compounds. Water is made of hydrogen and oxygen. Table salt is made of sodium and chlorine. There are millions of different compounds but only about 118 elements. It is like using just 26 letters to make millions of words.

Fun Facts

• Hydrogen is the most common element in the universe, making up about 75 percent of all matter.
• About 92 elements occur naturally on Earth. The rest were made by scientists in laboratories.
• The element francium is so rare that there may be only about 30 grams of it in the entire Earth at any time.

Did You Know?

Your body is made almost entirely of just six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. These six elements make up about 99 percent of your body mass!