| Ag |
symbol of the chemical element silver. |
| Al |
symbol of the chemical element aluminum. |
| aluminum |
a strong, light, silver metal that does not easily rust. Aluminum is a chemical element. (symbol: Al) |
| arsenic |
a poisonous substance that is one of the chemical elements. It can be either grayish white, yellow, or black. (symbol: As) |
| As |
symbol of the chemical element arsenic. |
| atom |
the smallest possible unit of a chemical element. The major parts of atoms contain protons, neutrons, and electrons. They are the basis of all matter in the universe. [1/2 definitions] |
| Au |
symbol of the chemical element gold. |
| B |
symbol of the chemical element boron. |
| Ba |
symbol of the chemical element barium. |
| barium |
a chemical element. Barium is usually found in compounds with other elements. (symbol: Ba) |
| Be |
symbol of the chemical element beryllium. |
| beryllium |
a hard, light, gray substance that is one of the chemical elements. Beryllium is sometimes combined with other elements to form an alloy. It is also used in building rockets. (symbol: Be) |
| Br |
symbol of the chemical element bromine. |
| bromine |
a poisonous, dark reddish brown liquid that is one of the chemical elements. It evaporates quickly and combines easily with other elements. (symbol: Br) |
| C2 |
symbol of the chemical element carbon. |
| Ca |
symbol of the chemical element calcium. |
| calcium |
a soft, silver-white substance that is one of the chemical elements. Calcium is found in many kinds of rocks. It is used by the body for building healthy bones and teeth. (symbol: Ca) |
| carbon |
a chemical element found in all living things. Pure carbon occurs as diamond or graphite. It is also often found in compounds with other elements. (symbol: C) |
| carbon dioxide |
Carbon dioxide is a gas that is made up of the chemical elements oxygen and carbon. This gas has no color or smell. Carbon dioxide is produced in many different ways. People put a little carbon dioxide into the air every time they breathe out. Carbon dioxide is also made by the burning of fuels, and it is created when plants die and decay. Carbon dioxide is often written CO2 and pronounced "see oh two." |
| chemical element |
Everything in our world and in space is made up of different chemical elements. Things like oxygen, lead, iron, and gold are some of these elements. Chemical elements are the very simple building blocks of all other things. They are pure substances. That means that they are made up of only one type of thing--one type of atom. The element iron, for example, is made up of only atoms of iron. It's not mixed with anything else. The chemical elements do mix with other chemical elements, though. That's how we get things like water, which is made up of two elements: oxygen and hydrogen. |
| chlorine |
a substance that is one of the chemical elements. It combines with sodium to form table salt. It is also used in making bleach. Chlorine is poisonous in its pure gas form. (symbol: Cl) |