1. Matter and Chemistry Matter: anything that has mass and volume Chemistry: the study of matter and it’s composition Atoms: The smallest unit of matter that still retains the properties of an element

2. Atoms Protons-positive charge, in the nucleus Neutrons-no charge, in the nucleus Electrons-negative charge, in the electron cloud Atomic #-the number of protons in an atom Atomic mass-the number of protons and neutrons in an atom To find neutrons, subtract at. # from at. mass

3. Elements Have a specific number of protons and certain characteristics There are 100+ known elements Most common: hydrogen and helium Each has a symbol designation used for abbreviating it’s name (ex: Na for sodium or O for oxygen)

4. Periodic Table The Periodic Table of the Elements was first made by Demitri Mendeleev in the 1800s The modern periodic table has elements arranged by atomic number The columns are the table are families, the rows are periods