Answer:
An atom cannot have 0.9 of a neutron.
Explanation:
Isotope of hydrogen is Protium, 11H, which has one proton, one electron and no neutron. Another isotope of hydrogen, deuterium has one proton, one electron and one neutron. There are no elements with 0.9 neutron. It is not possible for an element to have fraction of a neutron, the neutron is always a whole number.
