IONS MOLECULES AND COMPOUNDS

IONS MOLECULES AND COMPOUNDS

ION

         is an atom that has a positive or negative charge
                because it has unequal numbers of protons and electrons. 

        if an atom either gives up or gains electrons it becomes an ion.

IONIZATION

                is the process of givimg up or gaining electrons.

SYMBOL

         By writing the chemical symbol followed by the number of its positive or negative charges.

           eg.  Ca 2+  - stands for a calcium ion that has 2 positive charges, because it has lost 2 electrons. 

MOLECULE

The resulting combination when two or more  atoms share  electrons

             a. may consists of 2 atoms of the same kind

        eg. 
                O2-  a molecule of oxygen contains 2 atoms of oxygen.

             b.  may consists of 2 or more different kinds of atoms

eg. 
     Water- H2O-
       1 atom of  oxygen shares electrons with 2 atoms of  hydrogen

MOLECULAR FORMULA

Indicates the elements and the number of atoms of each element that make up a molecule.

eg.  
       O2-  a molecule of oxygen contains 2 atoms of oxygen.

COMPOUND

           Is a substance that contains atoms of two or more different elements

Most of the atoms inthe body are joined into compounds.

eg. H2O, Nacl

But a molecule of oxygen is not a compound because it consists of atoms of only one element.

FREE RADICAL

            Is an electrically charged atom or group of atoms with  an unpaired electrons in the outer most shell.

            having an unpaired electron  makes free radical 
                                                                                     unstable
                                                                                   highly reactive
                                                         destructive to nearby molecules

 
eg.  superoxide  O2-
         is formed by the addition of an electron to an oxygen molecule.     

Free radicals become stable by 
                         either giving up their unpaired electron to another  molecule
                                              OR
                         taking on an electron from another molecule.  
 
 In doing so , free radicle may break apart important body molecules.