Distance/ Time which means Distance is on horizontal and time is on vertical
1. Mass number = Protons + Neutrons
Mass number = 26 + 32 = 58
2. Let the element be Xy
58Xy26
3. The proton number of Strontium is 38.
Mass = 38 + 50 = 88
4. 88Sr38
5. Let the atom be Ab
72Ab32