ELEMENTS, COMPOUNDS & MIXTURES
Why it’s important: the food we eat, materials we use, and all matter
can be classified by these terms
Atoms
 Matter is made up of very small particles –
atoms
 (Different kinds of matter contain different
kinds of atoms)
Elements
 Basic building blocks of matter
 Contain only one type of atom
 Example: Gold only contains gold atoms
(symbol is Au)
 Example: Diamonds only contain _______
atoms (symbol is C)
 carbon
Elements continued
 Unique set of properties
 Classified as:
 Metals
 Nonmetals
 Metalloids
Metals
 Examples: copper (Cu), Gold (Au),
 Metallic luster
 Good conductors – heat & electricity
 Solid at room temp. (except mercury)
 Malleable (bent and pounded into various shapes)
 Ductile (drawn into wires w/o breaking)
 Most of the elements are metals
Nonmetals
 Examples: carbon, oxygen, hydrogen, nitrogen
 Dull in appearance
 Poor conductors – heat & electricity
 Many gases at room temp
 Solids are brittle
 Not malleable
 More than 97% of your body is made of nonmetals
Metalloids
 Characteristics of metals and nonmetals
 Solid at room temp
 Some shiny
 Many are conductors (not as good as metals)
 Found between metals and nonmetals on
periodic table
 Silicon- used to make electronic circuits in
computers and tv
Compounds
 Turn to Vocabulary in back of science notebook
 Vocabulary Word
 Substance
 Listen to the following sentence
 Elements such as a bar of gold or a sheet of aluminum,
are substances.
 Based on the sentence what do you think the word
substance means?
Substance
I think it means:
Definition: Matter of the same composition and
properties ; general term
Compounds
 What do you call the colorless liquid that flows
from the kitchen faucet?
 Water
 H2O
 Compound
 What do you think it means?
 Definition: Substance where smallest units are atoms
of more than one element bonded together
 Give an example
 H2O2?
Compounds:
flip back to note section & write
 Compounds have formulas
 H2O
Formula (elements & # of atoms of each
element)
subscript (tells you # of atoms of that element that
are present)
 Cannot be easily separated
EXAMPLES
 H2O (water): 2 Hydrogen atoms, 1 oxygen






atom
CO2 (carbon dioxide):
CO (carbon monoxide):
O2 (oxygen): 2 oxygen atoms
O3 (ozone):
2 H2O: 2 molecules of H2O for a total of : H=
O=
No matter the quantity of the compound the
formula always remains the same.
Mixtures
 Examples: blood, bucket of sand and water, salad,
salad dressing, chocolate chip cookie, strawberry ice
cream, orange juice
 Turn to Vocabulary section
 Mixtures:
 write what you think it means (try to use the word
substance in your definition)
 example
 Definition: 2 or more substances (elements or
compounds) come together but don’t combine to
make a new substance
Mixtures
flip back to note section
 Mixtures
 Examples: add 3 or 4
 2 or more substance come together (no new
substance)
 Proportions of substances in a mixture can be
changed without changing the identity of the
mixture
 What does that mean?
Mixture Examples: write down
 Air
 Mixture of nitrogen, oxygen & other gases
 Vary at different times and places
 It is still air
 Mix of sand & water
 Add more sand and you still have a mixture of
sand and water
Separating Mixtures
 Mixtures can be separated
 Examples of ways you can separate mixtures
 Liquids
 Add water to a mixture of sand and sugar
 Heat
 Sieves or filters
Homework:
 List 3 examples of compounds (cannot be any
given in class)
 List 3 examples of mixtures (cannot be any
given in class)
 Definition & 3 examples of the following
 Homogeneous mixture
 Heterogeneous mixture
 What type of mixture is sometimes difficult to
distinguish from a compound and why?
 Was your breakfast a compound,
homogeneous mixture, or a heterogeneous
mixture? Explain.