The electron configuration is incomplete. Assuming that you mean [Ar]4s23dy, here are the possibilities: y=1 Sc y=2 Ti y=3 V y=4 Cr (Actually [Ar]4s13d5) y=5 Mn y=6 Fe y=7 Co y=8 Ni y=9 Cu (Actually [Ar]4s13d10) y=10 Zn Basically the first row of transition metals, since their outermost electron shell is the 3d shell.
I presume that you are meaning "[Ar] 3d3 " ?
If so then this might be the electron configuration of V2+ Cr3+ (the most likely) or Mn4+
Cr is the symbol of chromium, and chromium(III) has a violet coloured hexaaquo-complex
Added:
Also possible that a part of the question was cut off or not typed and this was meant.
[Ar] 3d3 4s2
=============Vanadium.
Chromium i think......
you start with Ar- Argon then go to 3D with 4 electrons and takes you to chromium
Cr2+
cr
Mn