Mixtures, Elements and Compounds A Matter of Fact Mixtures, Elements and 
Compounds

Mixtures, elements, compounds Scientists like to classify things. One way that scientists classify matter is by 
its composition. Ultimately, all matter (anything that takes up space) can be classified as 
mixtures, elements and compounds.

Why isn’t it a good idea to classify matter by its phases? Because one kind of substance can exist in more 
than one phase – such as H20. And matter changes phases rather easily.  

Why isn’t matter classified 
according to its physical 
characteristics, such as color? Scientists wouldn’t find it very useful to group 
gold, sunflowers, and the sun together.

Scientists ask themselves these questions: Is the matter uniform (the same) throughout?
 Can it be separated by physical means? Can it be separated by chemical means?

By asking these questions scientists can classify 
matter into: Elements – simplest form of pure substance. They cannot be broken into anything else by physical or chemical means. Compounds – pure substances that are the unions of two or more elements. They can be broken into simpler substances by chemical means. Mixtures – two or more substances that are not chemically combined with each other and can be 
separated by physical means. The substances in a 
mixture keep their individual properties. Solutions – a special kind of mixture where one substance 
dissolves in another.

Can it be separated by physical means? If the answer is no, the matter is a pure 
substance.
 An element Or a compound

Elements Elements are the simplest pure substance. An element can not be changed into a simpler substance by 
heating or any chemical process. The smallest particle of an element that has the 
properties of that element is called an atom. An atom is the basic building block of matter. There are more than one hundred known elements 
in the universe listed on the periodic table of 
elements. These elements combine in such a way to create millions of 
compounds.

Elements All elements are made of atoms. Atoms of the same 
element are alike. Atoms of different 
elements are 
different.

Element

Compounds Compounds are also pure substances. But compounds are 
made from more than 
one element. Water is a compound. Water can be broken 
down into simpler 
substances – hydrogen 
and oxygen.

Compounds A compound is a pure substance composed 
of 2 or more elements that are chemically 
combined.

Hydrogen (H) + Oxygen (O) Examples of Compounds Compounds contain elements The elements combine + lose their original properties Compounds CAN be separated by chemical means The elements combine in specific ratios Sodium (Na) + Chlorine (Cl) NaCl Hydrogen (H) + Oxygen (O) H2O Carbon (C) + Oxygen (O) CO2

Mixtures A mixture is a combination of 2 or more 
substances that are not chemically 
combined.

Examples of Mixtures Properties of Mixtures: chicken noodle soup salad pizza Properties of Mixtures: Each substance in a mixture keeps its identity You can physically separate them They also contain elements, compounds, or both And they can be formed using any ratio of components

Mixtures may be homogeneous or heterogeneous The prefix “homo” indicates the same Homogeneous mixtures have the same 
appearance and properties throughout the 
mixture The prefix “hetero” indicates difference Heterogeneous mixtures consist of visibly 
different substances

Examples of Heterogenous mixtures Sand and pebbles Oil and water Powdered iron and powdered sulfur

Homogeneous Mixtures Milk, toothpaste, and mayonnaise are mixtures.

Comparing Elements, Compounds & Mixtures What are they made 
up of? Can they be broken 
down? If yes, how? Do they keep or lose 
their original 
properties? Draw what the 
particles look like.

Identify the following with as many terms as apply Table salt Salad Mayonnaise Italian dressing Pepsi Oxygen Hydrogen Water Mixture Element Compound Homogeneous Heterogeneous

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