Question

The sum of protons electrons and neutrons of the heaviest isotope of hydrogen

Answer 1

Tritium have1 proton,  1 electron ane 1 nerutron.

Sum = 1+2+1

        = 4 

Answer 2

1 protons ,1 electron and2 neutrons in isotope of hydrogen tritium.........

Atomic number =1
Mass number =3

Total sum =4