Content Outline for Teaching - Potosi School District - Home

4
Section 3
Content Outline
for Teaching
Compounds and Mixtures
Atoms, Elements,
and the Periodic Table
Underlined words and
phrases are to be filled
in by students on the
Note-taking Worksheet.
A. Substance—Matter that has the same composition and properties throughout
B. Compound—Substance whose smallest unit is made up of atoms of more than
one element
1. Chemical formula—tells which elements make up a compound as well as how
many atoms of each element are present
a. The subscript number tells how many atoms of the preceding element are
in the compound.
b. No subscript is used when only one atom of the element is present.
2. A given compound is always made of the same elements in the same
proportion.
C. Mixture—two or more substances mixed together which don’t make a new
substance
1. Unlike in compounds, the proportions of the substances in a mixture can be
changed without changing the identity of the mixture.
2. Examples: air, blood
3. Can separate mixtures easily
4. Homogeneous mixtures—the same throughout
5. Heterogeneous mixtures—you can see the different parts
Discussion Question
What is the difference between compounds and mixtures? Compounds are single
substances; mixtures are two or more substances mixed together. Compounds always contain
the same elements in the same proportion; the proportions of the substances in a mixture can
be changed. Mixtures can be easily separated; compounds cannot.
Atoms, Elements, and the Periodic Table 13