What distinguishes two different isotopes of an element is the number of neutrons contained in their nucleus. how many protons and neutrons are there in the nucleus of the heavier oxygen isotope, 18 8o? let z be the number of protons (the atomic number) and n the number of neutrons. separate your answers with a comma?

The Atomic Number and Atomic Mass of ¹⁸O₈ are 8 and 18 respectively.

Atomic Number:
                         Atomic Number of Element is the Number of Protons contained by the Element. So, there are 8 Protons in ¹⁸O₈.

Atomic Mass:
                     Atomic Mass of Element is the total number of Protons and Neutrons present in the Nucleus of that element.
So,
                    Atomic Mass  =  # of Protons + # of Neutrons

As the Atomic mass of ¹⁸O₈ is 18 and it has 8 protons, So # of Neutrons are calculated as,

                     # of Neutrons  =  Atomic Mass - # of Protons

                     # of Neutrons  =  18 - 8

                     # of Neutrons  =  10

Result:
             In ¹⁸O₈ Number of Neutrons are 10, Number of Protons are 8.

                                             Z  =  8 , n  =  10

Ido not understand. 

Isec i will do it and them i will let you know