Case 1 :
You're right, this is more hypothetical than feasible,
because vanadium is a metal that is only interested in
losing electrons to be oxidized to cationic form, not gaining
electrons to be reduced to anionic form.
The short answer is : both configurations are possible,
depending on other factors (that you needn't concern yourself with
at 'A' levels).
However, the more important lesson here is, the exam-smart
candidate will :
If this was a P1 qn, then consider both possible, but
(if both options are present, then) assume the more
direct answer, ie. 3d4 4s2.
If this was a P2 or P3 qn, then intelligently (ie. with
explanation) write both configurations in your
answer :
"When a particle with initial configuration [Ar] 3d^3 4s^2
gains an electron, it first attains an electron configuration of
[Ar] 3d^4 4s^2, which may (or may
not) subsequently rearrange itself (as observed in
the example of chromium) to have an electron configuration of [Ar]
3d^5 4s^1, by transferring an electron from its 4s orbital, to one
of its 3d orbitals, to achieve a more stable half-filled 3d
subshell."
Case 2 :
This is pretty straightforward. No rearrangement takes place (as
far as the electron configuration of the Fe2+ ion is
concerned, when asked at 'A' levels) because Fe2+ is ionic and
readily stabilizes itself in other ways (ie. as an alternative
to rearranging its electron configuration) such as by
forming ionic bonds, and/or coordination complexes (the
electrons-in-boxes diagram will include both its own electrons, as
well as those of the coordinate dative bonds donated by the
ligands).
Bottomline :
At 'A' levels, when removing electrons from d-block
elements, remember to just kick away electrons from the 4s
orbital (which is further away from the nucleus, thus easier to
remove), before removing any electrons from its 3d orbital (which
is nearer to the nucleus, thus more difficult to remove).
Hi all,
I have a question on the electronic configuration of particles,
especially when it uses the idea of the stability of 3d^5 4s^1
Some scenarios might be more hypothetical than feasible.
Case 1
What is the final configuration when a particle with initial
configuration [Ar] 3d^3 4s^2 gains an
electron?
[Ar] 3d^4 4s^2 or [Ar] 3d^5 4s^1?
Case 2
What is the final
configuration when a particle with initial configuration [Ar] 3d^6
4s^2 loses two electrons?
[Ar] 3d^6
or [Ar] 3d^5 4s^1?
Too many conflicting
approaches on the net, hope to clear things up here.
Thanks in
advance!
