write the electronic configuration of an inert gas isoelectronic with Sc³+
Answers
Answer:
Cobalt has an atomic number of 27. It's electronic configuration can be written as 1s
2
2s
2
2p
6
3s
2
3p
6
4s
2
3d
7
. Or it can also be written as [Ar]4s
2
3d
7
, where [Ar] represents the electronic configuration of Argon.
If two electrons are taken out from Cobalt, we are left with Co
2+
, that is 25 electrons, whose electronic configuration is 1s
2
2s
2
2p
6
3s
2
3p
6
3d
7
, or it can also be written as [Ar]3d
7
, which is clearly not the electronic configuration of a noble gas. Thus, Co
2+
is not isoelectronic to a noble gas.
Whereas, clearly all the other ions like Al
3+
, K
+
, Br
−
respectively have 10, 18, and 36 which represent the electron count of noble gases Neon, Argon, and Krypton respectively
Option D is the correct answer.