## Homework 9C.3

Ellis Song 4I
Posts: 102
Joined: Thu Jul 11, 2019 12:17 am

### Homework 9C.3

I'm having trouble naming compounds. I'm mostly struggling with figuring out how many molecules and what the roman numeral means.

Alexis Webb 2B
Posts: 124
Joined: Thu Jul 11, 2019 12:15 am

### Re: Homework 9C.3

The prefix before the ligand name tells you how many of that ligand there are. For example, pentaamminesulfatocobalt (III) chloride, there would be five (NH3) ligands. There is no prefix in front of the sulfate group so its just one SO4. The cobalt goes inside the brackets and in front of the ligands, while the chloride is outside the brackets. You can tell because it isn't attached to the long name for the compound. The roman numerals is the oxidation number, which is 3 in this case. Since there is a -2 charge from the SO4 and a -1 charge from the Cl, then the Co would need that oxidation number to keep the compound neutral. The oxidation number for this problem just helps you determine how much of the atom that is outside of the brackets you need in order to balance out the overall charge.

Chantel_2I
Posts: 109
Joined: Sat Sep 07, 2019 12:19 am

### Re: Homework 9C.3

When naming molecules, you first state the name of the cation, then the anion. Place the name of the complex anion or cation in brackets. Within the brackets, you name the ligands first, in alphabetical order. If there is more than one of any ligand, write the corresponding prefix for the ligand. If the ion is negative, change the -ide ending to -o. Then, still within the brackets, write the name of the metal and close the brackets. If the complex ion has an overall positive charge, the name of the anion follows the brackets. If the complex ion has a negative charge, the brackets go after the name of the cation.