An atom of xenon has a mass number of 127 amu. How many neutrons
does it contain? *

Answer:
73 neutrons.
Explanation:
Data obtained from the question:
Mass number of Xenon = 127.
Neutron number =...?
We can obtain the number of neutron present as follow:
Atomic number of Xenon = 54
Recall:
Atomic number = proton number = 54
Mass number = proton + neutron
127 = 54 + Neutron
Neutron = 127 – 54
Neutron = 73.
Therefore, 73 neutrons are present in the Xenon atom.