Protons = 20
Electron = 20
Neutrons = 20
Hope this Helps :)
Answer:

Explanation:
Hello,
In this case, since the reaction between potassium hydroxide and nitric acid is:

We can see a 1:1 mole ratio between the acid and base, therefore, for the titration analysis, we find the following equality at the equivalence point:

That in terms of molarities and volumes is:

Thus, solving the molarity of the base (KOH), we obtain:

Regards.
Answer:
I think
(d) All compounds contain the same elements in the same properties
The electron configuration for magnesium is 1s22s22p63s2