The first one is correct cause first of all it's atomic number is 7 and second of all it's atomic mass is about 15
        
             
        
        
        
answer=H+]=10-7 
explain=the same way, a solution with a pH of 5 contains 10-5mol/l of hydrogen ions, a solution with a pH of 6 contains 10-6mol/l of hydrogen ions, while the solution with a pH of 7 contains 10-7mol/l of hydrogen ions
 
        
             
        
        
        
Answer:
go to a calculator and see the answer then make the hypothisis which is the answer
Explanation:
magic