Write down the electronic configuration of:
(i). `Cr^(3+)`
(ii). `Prn^(3+)`
(iii). `Cu^(o+)`
(iv). `Ce^(4+)`
(v). `Co^(2+)`
(iv). `Lu^(2+)`
(vii). `Mn^(2+)`
(viii). `Th^(4+)`

Explanation

To find the electronic configurations of the given ions, we first need to determine the electronic configuration of the neutral atom and then adjust it according to the charge of the ion.

### Step-by-Step Solution:

1. **Cr^(3+) (Chromium)**
- Neutral Chromium (Cr) has an atomic number of 24.
- The electronic configuration of Cr is:
\[ \text{Cr: } 1s^2 2s^2 2p^6 3s^2 3p^6 3d^5 4s^1 \]
...