Week 6 Lesson
Chemical Classification of Matter
March 21, 2003
Biological and Chemical Weapons Would Slow but Not Stop Troops
By NICHOLAS WADE
New York Times
Bell Ringer: What is the name for the table above? What does each individual block on this table represent? If you take two of the elements and combine them is there a different name for that substance?
Objective: SWBAT chemically classify all matter into one of 3 categories: element, compound or mixture. They will also know different properties of elements and be able to futher break down the category of mixture into heterogeneous or homogeneous.
Lecture/Discussion:
There are three groups that matter can be chemically classified as. These groups are elements, compounds, and mixtures.
ELEMENTS
The first of these groups is elements. Elements cannot be broken down into simpler substances in a chemical reaction. Each element has it's own name and symbol. All elements are classified as metals, nonmetals, or semimetals.
Metals are those elements that are lustrous, ductile, malleable, sectile, and conductors of heat and electricity. Of the pictures below which are those of metals.
Below are the defintions of some terms that you may not know. By knowing the terms below it can help you to classify elements as metals.
- Ductile - this is the ability of a metal to be drawn into wires
- Malleable - ability to be hammered into sheets
- Sectile - ability to be cut into sheets
If metals have the qualities that are talked about above what are some qualities of nonmetals? Does carbon conduct heat or electricity? Click here to find a list of some qualities of nonmetals.
Semimetals are a mixture of the qualities of metals and nonmetals. Semimetals are lustrous but brittle and semiconductors of heat and electricity. Examples of semimetals are silicon and arsenic.
COMPOUNDS
A compound is a homogenous chemical state of matter that can be broken down into simpler substances, usually elements, by chemical reactions. There are a few important things to remember about compounds.
- They are always made from two or more elements
- Compounds are physically and chemically different from the elements that they are made up of.
- Compounds can be seperated only by chemical change
MIXTURES
Mixtures are the last category of chemical classification. A mixture is a heterogeneous or homogeneous chemical state of matter that can be seperated into simpler substances by physical methods. What are some common mixtures that you can think of?
Mixtures:
- can be composed of two or more substances
- may be made in any proportion
- do not give off any signs of a reaction
- composed of substances taht retain theri properties
- are always seperated by physical methods
Activities: Test yourself here
Closing: What are the chemical classifications of matter and how do they differ?