how to find the charge of an ion

CBR600RR · Mar seven, 2013

How do you find out the charge of a compound/ion when a question only says "Calcium ion"? Practice I need more info on information technology, am I missing something?
I'll give a few examples:
Sulfite ion
sulfur dioxide
sulfur trioxide

I need to know the number that goes in front of the charges. Please don't just give me an answer for these 3, if you could besides explain how you got the answer it would greatly be appreciated. Thanx.

Gokul43201

First you demand to know the about mutual oxidation states of several different elements. These are piece of cake to remember if you know the groups that these elements belong to in the Periodic Table. Grouping I has Li, Na, One thousand (the others are less of import), and all these have the oxidation land of +1. Group Ii has Be, Mg, Ca and these have oxidation country +2. The transition metals, from Sc to Zn and beneath have unlike oxidation states that are useful to call up for the mutual elements. In group Three, B, Al, Ga have ox. number +iii. Gr. Four has C, Si, Ge, Sn, which have ox. no. +4. From Gr Five on the oxidation numbers are negative (ox. no. = Gr. no. - 8). So Gr. 5 (N, P) has ox. no. -3. Gr. Vi (O, Due south) has ox. no. -two. Even so, N is frequently considered +5, but sometime +3 and S can exist either +6 or +iv (which one it is depends on the compond, and can be adamant from the other elements in that compound). Gr. Seven (F, Cl, Br) is e'er -1. And Gr. VIII has ox. no. 0. Then, elements of Gr. Eight never form compounds.

To notice the oxidation no. of a radical (like sulfite, nitrate, etc.) you lot just add the oxidation states of the different elements in information technology.

Sulfite is SO3(2-). We know that each O is -2, so the three O's brand up -vi. And so, SO3(2-) has a total charge of -2. Let the oxidation state of S be 10. Then x + iii(-ii) = -2. Or 10-6=-2. Hence, x=iv. The ox. no. of Southward is +four in this case.

In a compound (or stable chemical element), the total accuse is ever 0. So, the sum of positives must equal the sum of the negatives.

So, in sulfur dioxide (SO2) , the total ox. no. is 0. We know for sure that O is -ii. And there are ii O's, so the total negative charge is -4. So, for the compound to have zero total charge, S must be +four.

What would be the ox. no. of S in sulfur trioxide (SO3) ?

GCT

Your questions pertains to formal charges, and you should discover this topic in your volume and report it. As for elements, ways to find the mutual charges that elements employ is to discover which grouping they are in.

CBR600RR

Thanx, for the aid, just I just asked my teacher. There are ceratain compounds and elements that we simply demand to remember. The charges are given in the book, just thanx anyway, i'm certain sick have more questions before long.

Gokul43201

You demand to recollect the elements, the compounds can be figured out. For many of the elements, knowing the position in the periodic tabular array helps with the memorizing.