## Naming Question

Aj1156
Posts: 34
Joined: Fri Sep 28, 2018 12:22 am

### Naming Question

For the coordination compound [FeCl(OH2)5]+

What would the charge be of Fe? Can someone please also explain the charge of each atom or molecule?

Sarah Zhao 4C
Posts: 64
Joined: Fri Sep 28, 2018 12:28 am

### Re: Naming Question

OH2 has a charge of 0. Its water: H20 or OH2. So having 5 of them would still make the charge 0.
Cl has a charge of -1. It is a halogen, so it will always have a charge of -1
The total charge of the coordinate compound is +1.
So to get the compound from the -1 provided by the Cl to the +1 of the compound, Fe would need to take on a charge of +2.
Fe is a transition metal, so it can take on so many different charges. Pretty much, everything except transition metals will have the charge assigned to them on the periodic table. There are SOME exceptions.

BenJohnson1H
Posts: 68
Joined: Fri Sep 28, 2018 12:17 am

### Re: Naming Question

Fe has a +2 charge. You know this because the entire ligand has a 1+ charge while Cl has a 1- charge. Thus the ligand must contain two positive charges to cancel this Cl's 1-. Since OH2 is neutral, these two positive charges are derived from Fe, giving it a 2+ charge.

arif_latif_2G
Posts: 60
Joined: Fri Sep 28, 2018 12:23 am

### Re: Naming Question

The sum of the oxidation numbers in a polyatomic ion is equal to the charge of the ion. The water molecules are neutral (0) so can be ignored. Cl is -1. So to find Fe, the charge of Fe + the charge of Cl = 1 (charge of the ion) so this becomes x - 1= 1, which makes Fe a charge of +2.

Here are some general rules to follow:
The oxidation number of a free element is always 0.
The oxidation number of a monatomic ion equals the charge of the ion.
The oxidation number of H is +1, but it is -1 in when combined with less electronegative elements.
The oxidation number of O in compounds is usually -2, but it is -1 in peroxides.
The oxidation number of a Group 1 element in a compound is +1.
The oxidation number of a Group 2 element in a compound is +2.
The oxidation number of a Group 17 element in a binary compound is -1.
The sum of the oxidation numbers of all of the atoms in a neutral compound is 0.
The sum of the oxidation numbers in a polyatomic ion is equal to the charge of the ion.

Jonathan Cheng 3C
Posts: 30
Joined: Fri Sep 28, 2018 12:23 am
Been upvoted: 1 time

### Re: Naming Question

Fe would have a charge of 2+ because OH2 has a charge of 0 so it does not affect the charge of the molecule. Cl has a charge of 1- and the overall charge of the molecule is 1+. Thus, Fe would have a charge of 2+ to allow the overall charge of the molecule to be 1+

yuetao4k
Posts: 60
Joined: Fri Sep 28, 2018 12:27 am
Been upvoted: 1 time

### Re: Naming Question

OH2 has a charge of zero. Cl has a charge of 1-, so that means Fe has a charge of 2+ because the overall charge of the compound is 1+.