Answer
The name of $Mn_2(SO_4)_3$ is : "Manganese (III) sulfate".
Work Step by Step
1. Identify the positive ion, and name it.
$Mn^{3+}$ is the positive ion.
So, the first name of the compound will be: "Manganese (III)";
2. Identify the negative ion, and name it.
$S{O_4}^{2-}$ is the negative ion.
As we can see in Table 2.2 (Page 58), this ion is called "sulfate".
3. Putting those two names together:
Manganese (III) sulfate.
