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PERIODIC TABLE
Lesson 3 - Page 2

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In a molecule, two or more atoms share electrons through a chemical bond and are electrically stable.   The term “molecule” is French for an extremely small participle and was introduced by the French philosopher Rene Descartes in the 1620’s.  Even two atoms of the same element can be a molecule.  Oxygen is a diatomic molecule, which is made of two atoms of oxygen (O2). Other diatomic molecules include hydrogen, sodium, chlorine, bromine, and iodine. Molecules are very small ranging in size from two atoms to macromolecules like DNA composed of billions of atoms.  Molecules can be created inorganically (without life) or organically (with life).     

Compounds are two or more different elements that are joined chemically together.  Compounds are everywhere.  It is the chemical substances that you see, feel, taste, and even eat everyday.  We are made of compounds, the Earth is made of compounds, and even the components of space are made of compounds.

Elements are present in compounds as fixed amounts parts by mass.  The formed molecule would have a fixed number of atoms.   The property of a compound is different from those of the elements that make it up.  Water, a liquid is made up of two gases, hydrogen and oxygen. Compounds can be broken into its component elements through various methods.   Through electrolysis water (H2O) can be chemically forced into making oxygen and hydrogen.  There will be twice the volume of hydrogen as there is oxygen. 

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