Solute particles can be atoms, ions or molecules.
Explanation:
Solute is the material which has to be mixed in the solvent to prepare a solution. So the concentration of solute should be less than the solvent. Also the solute and solvent should be of same nature other they will not dissolve with each other. The solute can be made up of atoms, ions or molecules depending upon the solvent. If the solvent concentration is in moles, then the solute concentration can be taken as atoms, ions or molecules. Also the saturation point plays a main role in deciding the kind of particles taken for the solute.
Answer :
121.5 <span>
μCi
Explanation : We have Ce-141 half life given as 32.5 days so if the activity is 3.8 </span><span>μci after 162.5 days of time elapsed we have to find the initial activity.
We can use this formula;
</span>

3.8 /

=

((0.693 X 162.5 ) / 32.5) = 121.5
<span>
On solving we get, The initial activity as 121.5 </span>μci
%C= 12/12 + 2·16=0,273=27,3%.
I forgot what quantum means to be honest, the Bohr model In atomic physics, the Bohr model or Rutherford–Bohr model, presented by Niels Bohr and Ernest Rutherford in 1913, is a system consisting of a small, dense nucleus surrounded by orbiting electrons—similar to the structure of the Solar System, but with attraction provided by electrostatic forces in place of gravity. After the cubical model (1902), the plum pudding model (1904), the Saturnian model (1904), and the Rutherford model (1911) came the Rutherford–Bohr model or just Bohr model for short (1913). The improvement over the 1911 Rutherford model mainly concerned the new quantum physical interpretation.