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