Answer:
This question is incomplete
Explanation:
This question is incomplete, however, element R and element Q having the same number of valence electrons means they belong to the same group in the periodic table which is the reason for there similar chemical behavior (as elements in the same group tend to have the same chemical properties).
Element R having fewer energy level (or electron shell) than element Q shows element R has fewer number of electrons than element Q and can be found earlier in the periodic table (or group in particular) when compared to element Q
The answer here is neutrons
It is C 2 1 2 1
You have to 1st balance the nitrates then balance the silvers to get the coefficients