Students were shown models of two atoms and asked to make a list of similarities and differences between the models. Which of the statements about the atomic models shown is correct?

A) Both models represent atoms with the same atomic number.
B) Both models represent atoms with the same atomic mass.
C) The model on the left is an ion and the model on the right is an isotope.
D) The model on the left is an isotope and the model on the right is an ion.

An electrons position cannot be known precisely only it's probability of being in a certain location can be known

A3.37-mg sample of protein was chemically digested to convert its nitrogen into ammonia and then diluted to 100.0 ml. then 10.0 ml of this solution was placed in a 50-ml volumetric flask and treated with 5 ml of phenol solution plus 2 ml of sodium hypochlorite solution. the sample was diluted to 50.0 ml, and the absorbance at 625 nm was measured in a 1.00-cm cuvette and found to be 0.486. for reference, a standard solution was prepared from 10.0 mg of nh4cl (molar mass = 53.49 grams/mole) dissolved in 1.00 l of water. then 10.0 ml of this standard was placed in a 50-ml volumetric flask, treated in the same manner as the unknown, and the absorbance found to be 0.323. finally, a reagent blank was prepared using distilled water in place of unknown, it was treated in the same manner as the unknown, and the absorbance found to be 0.076. calculate the weight percent of nitrogen in the protein.

If anyone would be able to me out with these three questions it would be these are from the chem 2202 course.