An ion with mass number 56 contains 3 units of positive charge and 30.4% more neutrons than electrons will have  Z as

Mass number (N + P) = 56Let Protons be = PThen, neutrons = (56 - P) and electrons in x3+=(P−3)  Neutrons =(P−3)30.40100+(P-3) =(P−3)1.3040 ∴mass number=no.of p+no.of n 56=P+(P-3)1.304  (P−3)1.3040=56−P 56=2.304P-3.912 59.912=2.304 P P=26=Z