The mass number of an isotope of an element is 298. If its nucleus has 189 neutrons, what is its atomicÂ number?

The mass number of an isotope of an element is 298. If its nucleus has

1.	The mass number of an isotope of an element is 298. If its nucleus has 189 neutrons, what is its atomicÂ number?
A.	298
B.	189
C.	109
D.	487
Answer» D. 487