Formation of Compound
We
get chemical formula of molecule by writing valence of 1st atom in
front of 2nd atom and valence of 2nd atom in front of 1st
atom.
Example: valence of carbon is 4 and oxygen is 2, write
4 in front of O and 2 in front of C in subscripts as shown below.
C2O4
as we see, both valences are multiple of two so
divide it by two to get CO2 formula.
Similarly,
Na+
+ CO3-2 ---> Na2CO3
Al+3
+ SO4-2 --->
Al2(SO4)3
Mg+2
+ N-3 --->
Mg3N2