Now, that we've discussed
electron configurations of atoms,
we can talk about electron
configurations of ions.
And remember,
an ion is very similar to an atom,
except it's gonna vary with
the number of electrons that it has.
So, if we look at sodium and
compare that to the electron configuration
that we would have to write for
sodium plus or the sodium plus cation.
We need to remove one electron
when we go from the sodium atom
to the sodium plus cation.
So, now our electron
configuration becomes 1S2,
2S2, 2P6 If we look at magnesium,
magnesium's common
oxidation state is 2 plus.
So, when we write the electron
configuration for magnesium 2 plus
it's gonna be the same as magnesium,
except we need to remove two electrons.
So, this is gonna be 1s22s22p6 for
Aluminum.
Aluminum's oxidation state is 3+ so
we need to remove three electrons,
so that's going to give us an electron
configuration of 1S2 2S2 2P6.
Notice that for both sodium plus,
magnesium 2+ and aluminum 3+,
our electron configurations
are all going to be 1S2,
2S2, 2P6 which is the neon Nobel gas core.
And remember, the nobel gas electron
configurations are very stable.
And this is actually why sodium
wants to be a +1 charge.
Magnesium a plus two and aluminum
a plus three, because they will exist
as the noble gas configuration,
which would be in this case, neon.
It's a very stable arrangement, and
all the quantum mechanics theories that we
looked at all show that electrons wanna
exist in the most stable possible.
So, now let's look at some anions and
the difference between fluorine and
the F-anion is we need to add an electron.
So, now our electron configuration
becomes 1s22s22p6 instead of 2p5.
The same thing for
nitrogen, notice that nitrogen,
when it becomes an anion needs three more
electrons to get to that noble gas core.
So, it's going to be 1s2 2s2 2p6.
So again, the F- and the N3-
electron configurations also have the Neon
noble gas core and in addition,
these are very Be stable.
So, this is why the fluorine anion
wants to gain one electron and
the nitrogen anion needs three electrons,
it's because they wanna reach.
That stable arrangement or
that noble gas core of electrons.
