Chemical Elements and Compounds

An element is the smallest building block of matter and can’t be broken down to two or more different matters.

Hydrogen and helium are the lightest elements

Molecule— group of atoms chemically joined together

Compound— two or more elements joined together chemically and can be made up of two atoms or hundreds of them.

You cannot see carbon dioxide. “T or F”

Helium is lighter than air and found everywhere in the universe.

Hydrogen is the second most common element.

At room temperature oxygen is a gas. (gas, solid, liquid?)

Earth atmosphere is 20% oxygen.

(Chemical composition of sugar?) Sugar also known as glucose is a molecule made of six carbon atoms, 13 hydrogen atoms and 6 oxygen atoms.

VOCABULARY  WORDS

Refrigerant—A refrigerant is a substance or mixture, usually a fluid, used in a heat pump and refrigeration cycle.