Core
Reactions: Redox
Slide 8 of 42
Valence and Charge
Valence relates to the number of electrons on the outermost
shell of the atom of an element.
–In
case of elements in periods 1-3, valence is equal to their group.
Since the loss of the valence electrons results in a positively
charged ion, in the case of main group metals, the positive charge
on the ion equals the number of valence electrons.
–For
example, valence of Na is 1 and charge is 1+, valence of Ca is 2 and charge is
2+, valence of Al is 3 and charge is 3+.
With non-metals, valence equals the group number.
Charge on their ion however is negative and is generally equal
to the number of electrons required to complete the valence
shell.
–For
example, valence of nitrogen is 5 and charge on ion is 3-, oxygen is 6 and charge
is 2-, fluorine 7
and charge 1-,
etc.