Elements, compounds and mixtures

An element is a material composed of a simple type of atom, a compound is a substance formed by two or more elements that combine chemically and a mixture is the combination of substances, the same or not, that can be separated by physical methods.

DefinitionA substance formed from an atom.A substance made up of chemically bound molecules or ions.Set of two or more substances.
Separation techniqueDoes not applyDoes not applyFiltration





No metals









Table salt






The element is a pure chemical substance formed from an atom . It is characterized because it cannot be divided or transformed by a chemical reaction.

The elements discovered to date are 118 and are classified in the periodic table. Each element differs mainly by atomic number , which is nothing more than the number of protons found in the nucleus of the atom.

Element types

  • Metals : are the elements characterized by conducting electricity, being malleable and showing shine. For example: gold Au, iron Fe, sodium Na.
  • Non-metals : these are the elements characterized by not being good conductors of electricity, non-magnetic and non-malleable. Example: oxygen O, chlorine Cl and neon Ne.
  • Metalloids : those elements that have some characteristics of metals and non-metals. Example: arsenic As, silicon Si, boron B.

Examples of elements

Carbon C

Carbon, whose symbol is C, is the key element of organic compounds. Its atomic number is 6 and it is also found in graphite and diamond.

Hydrogen H

Hydrogen, whose symbol is H, is the most abundant element in the Universe. Its atomic number is 1 and it is found in nature as a diatomic element H 2 .

You may be interested in seeing Atoms and molecules .


A compound is a pure chemical substance made up of a particular set of molecules or ions that are chemically bound together. They may be:

  • molecular compounds linked by covalent bonds;
  • salts linked by ionic bonds;
  • compounds of metal with metal joints; and
  • complex compounds.

Types of compounds

  • Inorganic compounds : are those compounds in whose composition there are no bonds between carbons. Example: water H 2 O, sulfuric acid H 2 SO 4 , silver nitrate AgNO 3 .
  • Organic compounds : are those compounds where carbon is the base element in the construction of the molecule. Example: ethanol H 3 C-CH 2 OH, proteins and carbohydrates.

It may interest you to know about Organic and inorganic compounds .

Examples of compounds in everyday life


Water is a chemical compound formed by the chemical union of two hydrogen atoms and an oxygen atom H 2 O. Water is the most essential compound for the maintenance of life on the face of the Earth.

Table salt or sodium chloride

The salt we use in the kitchen is sodium chloride NaCl, which is an ionic compound, that is, between the elements sodium and chlorine, ionic bonds are established, where there is transfer of electrons.


Glucose, with the formula C 6 H 12 O 6 , is an organic compound made up of carbon, hydrogen and oxygen. It is synthesized in plants by the photosynthesis process and is used by heterotrophic organisms as a source of energy.

You may be interested in knowing more examples of organic and inorganic compounds .


A mixture is the combination of various elements and / or molecules that are not chemically bound . It differs from pure substances, such as elements and compounds, in that the components can be separated by various physical techniques.

Mix types

  • Homogeneous mixture : it is one whose composition is uniform and each part has the same properties. For example: the mixture of water and vinegar, the mixture of alcohol and water.
  • Heterogeneous mixture : it is one in whose composition the parts of the mixture can be distinguished. For example: the mixture of oil and vinegar, the mixture of a fruit juice.

Examples of mixtures in everyday life


Air is a mixture of 78% nitrogen, 21% oxygen, and the remaining 1% is represented by argon, water vapor, and carbon dioxide.

Sea water

Seawater is a mixture made up of water, ions, salts, and a variety of other molecules.


Mayonnaise is a mixture of fat, protein and water emulsion. To prepare mayonnaise, you have to beat the egg with oil and salt in a certain proportion.

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