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.
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