In: Chemistry
Write the electronic configuration of the O2− ion.
In order to write a correct electronic configuration, one must keep in mind three rules, which are as follows:
Aufbau principle: This principle states that the orbitals are filled in the order of their energy, that is the orbitals with lower energy would be filled first.
Pauli's exclusion principle: This principle states that no two electrons should have the same set of all the 4 quantum numbers.
Hund's rule: This rule states that the electron pairing in an orbital in a subshell wouldn't happen until and unless all the orbitals in a subshell are half-filled.
Now, let's get to the problem at hand:
O2- could mean any of the two things: or
So let's start with :
The electronic configuration for is:
Now let's look at the configuration of :
is a molecule so, here, we're going to use molecular orbital theory to arrive at the electronic configuration:
So, the electronic configuration for is:
This configuration can be more plausibly seen in the image given below: