The pair of ions haivng same electronic configuration is-Fe+2, Co+2Fe+3, Co+3Fe+2, Co+3Cr+2, Fe+3

The electronic configuration of an atom is determined by the number of electrons in its atomic orbitals. When an atom loses or gains electrons, it forms an ion and its electronic configuration changes.

Let's find out the electronic configuration of each ion:

1. Fe+2: The atomic number of Fe (Iron) is 26. So, its electronic configuration is [Ar] 3d6 4s2. When it loses 2 electrons to form Fe+2, the electronic configuration becomes [Ar] 3d6.

2. Co+2: The atomic number of Co (Cobalt) is 27. So, its electronic configuration is [Ar] 3d7 4s2. When it loses 2 electrons to form Co+2, the electronic configuration becomes [Ar] 3d7.

3. Fe+3: When Fe loses 3 electrons to form Fe+3, the electronic configuration becomes [Ar] 3d5.

4. Co+3: When Co loses 3 electrons to form Co+3, the electronic configuration becomes [Ar] 3d6.

5. Cr+2: The atomic number of Cr (Chromium) is 24. So, its electronic configuration is [Ar] 3d5 4s1. When it loses 2 electrons to form Cr+2, the electronic configuration becomes [Ar] 3d4.

From the above, we can see that the pair of ions having the same electronic configuration is Fe+3 and Co+3.