Answer:
5 neutrons.
Explanation:
The following data were obtained from the question:
Mass number = 9
Atomic number = 4
Charge = +2
Neutron number =.?
Next, we shall determine the number of protons in the beryllium ion. This can be obtained as follow:
The atomic number is simply the number protons present in the atom. Thus,
Proton = Atomic number
Atomic number = 4
Proton = Atomic number = 4
Finally, we shall determine the Neutron number as follow:
Mass number = 9
Proton number = 4
Neutron number =.?
Mass number = Proton + Neutron
9 = 4 + Neutron
Collect like terms
Neutron = 9 – 4
Neutron = 5
Thus, there are 5 neutrons b present in the beryllium ion.
