1. Chapter 2 Matter & Its properties
We have defined matter as anything that has mass and occupies space. All matter is composed of atoms. Elements and compounds are made up of atoms.
An atom is the smallest unit of an element that has the properties of that element. An element is a pure substance and can not be broken down into simpler substances.

2. A compound is a pure substance that is made of two or more elements that can be broken down into simpler substances.
NaCl  Na + Cl2

3. Matter can exist in four states or phases (three are found naturally on earth)
Solid
Liquid
Gas
Plasma (found in the interior of stars)

4. Note that energy must be supplied to go from one state or phase to another:
Solid  liquid  gas
Solids have a fixed volume and shape
Liquids have a fixed volume and take on the shape of their container.
Gases have neither a fixed volume nor shape

5. In addition to phase changes matter can undergo other physical changes:
Physical changes do not produce any new substances.
What happens when a ice cube when heat is supplied?
What about when sugar dissolves in water?

6. Chemical changes produce new substances.
In a chemical reaction one or more substances, the reactants, are converted to one or more new substances, the products.

7. A physical property is one that describes a physical change
A physical property is one that describes a physical change. When considering phase changes, the melting point of a substance is a physical property.
A chemical property describes the chemical change. Paper undergoes a chemical change when it burns in air (oxygen), so the ability of paper to react with oxygen is a chemical property.

8. Compounds and elements are both pure substances.
Compounds are a chemical combination of two or more elements.
Mixtures are physical combinations of two or more pure substances.
Mixtures that are uniform in composition are called homogeneous mixtures (salt in water).

9. Mixtures that are not uniform are heterogeneous mixtures (sand in water)

10. Section 2.3 Elements
I mentioned previously that elements are composed of atoms. The periodic table lists all the known chemical elements.
The columns are called groups or families-there are 18 of them.
The rows are called periods-there are 7.
See page 46.