The number of neutrons in the dipositive zinc ion
Hi Vijay,
Mass number = Number of protons + Number of neutrons
Atomic number = number of protons or number of electrons
Atomic number of zinc = 30 i.e., has 30 electrons. In dipositive ion 2 electrons are lost, so, 28 electrons are present.
Mass number = 70
70 = 30 + Number of neutrons
Thus number of neutrons in dipositive zinc ion with mass number 70 is 40.
Feel free to ask doubts in the Comment Section.
I hope this information helps you.
Good Luck!