Is their an easy way to workout chemical formula's?
Answers:
For ionic compounds, yes there is (within limitations of course!).
If you look at the valency or group number of the ions concerned then all you need to do is make sure the +ves and -ves cancel each other out.
For instance.Na is in group 1, so is 1+.needs 1- to cancel it out, this can be found in group 7 ions such as F-, Cl- etc, hence formulae would be NaF, NaCl etc
If Na was reacted with a group 6 element such as 0 which is 2-, then you'd need 2 x Na+, so formula would be Na2O.
And so on..
The exception is for compound anions such as sulphate. nitrate etc, for which you just need to learn the valency then apply the rules as above
Sweetheart, work on your english too.there, not their.
Yes.
i think if you know the valencies of the elements you can get at the chemical formula of their compounds
You have to know (or look up) the valency (combining number) of each element or ion. Then if they are the same value there will be just one of each ion or atom. e.g. iron II ( Fe 2+) has a valency of 2 and so does sulphate (SO4 2-) so the formula is FeSO4. If the values are different then 'swap over' the values. E.g. sodium has a valency of +1 and carbonate (CO3) has a valency of -2. When you swap over the numbers there will be 2 sodiums and 1 carbonate to give Na2CO3. Phosphorus has a valency of 5 and oxygen a valency of 2. Swapping the numbers gives the formula of phosphorus oxide as P2O5. If there is more than one of a group of atoms (as in sulphate SO4) the group has to be in brackets. E.g - Aluminium has a valency of 3 and sulphate a valency of 2. Swapping the numbers over would give Al3(SO4)3
the SO4 is in brackets otherwise it would look like SO43 which is wrong. That's about as easy as you can get!
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