Valency, Oxidation State and Ionic Compounds.
When a metal reacts with a non-metal,
the metal will lose electrons to form a positive ion
and the non-metal will gain electrons to
form a negative
ion.
The compound which is formed will be
ionic.
It will form a giant structure (also called a giant ionic
lattice).
If you do not know whether an
element is a metal or
a non-metal
see the periodic table.
The valency (combining
power) of a metal is the
same
as its oxidation state (the charge on
the ion).
The number of electrons that a metal will lose
is the same as its group number in the
periodic table.
A metal in group
1 will form a 1+
ion
(Valency 1,
oxidation state 1+).
A metal in group
2 will form a 2+
ion
(Valency 2, oxidation
state 2+).
The number of electrons that a non-metal will gain
will be 8 minus its group number.
A non-metal in group 6 will form a 2- ion
(Valency
2, oxidation state 2-).
A non-metal in group 7 will form a 1- ion
(Valency
1, oxidation state 1-).
A non-metal ion is negative
because it has gained electrons.
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