1. ANYTHING THAT TAKES UP SPACE AND HAS MASS.2. ALL MATTER IS MADE UP OF ATOMS.

1. THE SMALLEST UNIT OF A CHEMICAL ELEMENT.

1.EACH ELEMENT IS MADE OF ONLY ONE KIND OF ATOM.2.THERE ARE ABOUT 120 ELEMENTS.

1.A LIST OF ALL OF THE CHEMICAL ELEMENTS THAT EXIST IN THE UNIVERSE.2. CATEGORIZES, ORGANIZES ELEMENTS ACCORDING TO THE PROPERTIES THEIR ATOM.

1. FORMED WHEN 2 OR MORE ATOMS JOIN TOGETHER.2.THESE MAY BE 2 OF THE SAME ATOM OR 2 DIFFERENT ATOMS.

1.FORMED WHEN 2 OR MORE DIFFERENT ATOMS ARE JOINED TOGETHER.2.NOTE: ALL COMPOUNDS ARE ALSO MOLECULES, BUT NOT ALL MOLECULES ARE COMPOUNDS.