mid year science review

chemistry, earth history, infectious diseases

Groups and Periods

Groups: elements in the same vertical column of the periodic table. Periods: a horizontal row of elements in the periodic table.

law of conservation of mass

The principle that the total amount of matter is neither created nor destroyed during any chemical or physical change.

physical and chemical properties

physical property: a characteristics of a pure substance that can be observed with out changing it into another substance. chemical property: a characteristic of a pure substance that describes its ability to change into a different substance.

physical and chemical changes