Atom Structure for Scandium  

There are 21 protons and 24 neutrons in the nucleus.  The electron configuration is -8-9-2.  Scandium is a transition metal.  Most transition metals have atomic radius that decrease from left to right because of the increasing nuclear charge.

 Number of Energy levels:
   4
  First Energy Level
   2
  Second Energy Level
   8
  Third Energy Level
   9
  Fourth Energy Level
   2