Chemistry Query!! (1 Viewer)

[lookoutastroboy]

Hey guys,

Just wanted to know something about some of the common ions such as CO3- (carbonate - minus 1 at the top) and SO42- (sulfate - minus 2 at the top) - how do these ions get these valencies or, in other words, how does one determine them?

In some chem eqns for other types of ions, the negative numbers or positive numbers (valencies) are already present - how can you determine them yourself if they are not there?






Any help would be great,
Cheers, lookoutastroboy

 

[muzeikchun852]

Hey guys,

Just wanted to know something about some of the common ions such as CO3- (carbonate - minus 1 at the top) and SO42- (sulfate - minus 2 at the top) - how do these ions get these valencies or, in other words, how does one determine them?

In some chem eqns for other types of ions, the negative numbers or positive numbers (valencies) are already present - how can you determine them yourself if they are not there?

determine by their groups:
group I - +1
group II - +2
group III - +3
group IV - N/A
group V - -3
group VI - -2
group VII - -1
group VIII - 0

metal is normally positive and non-metal is normally negative.

 

[pwoh]

determine by their groups:
group I - +1
group II - +2
group III - +3
group IV - N/A
group V - -3
group VI - -2
group VII - -1
group VIII - 0

metal is normally positive and non-metal is normally negative.

I think he means polyatomic ions.

Adding the valencies of the elements seem to work for many of these, but not all (Especially not the ones containing oxygen). Not sure how to calculate for any polyatomic ion specifically :S

(E.g. NH4 = -3 + 2x2 = 1
OH = -2 + 1 = -1
HCO3 = +1+4-2x3 = -1
CO3 = +4-2x3 = -2 [it's -2, not -1])

 

[ohexploitable]

Just use them a lot in equations and eventually you'll remember them.