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?

SubstanceI 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

Mixturesflip 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.