Answer:
Option C. 1
Explanation:
Step 1:
Determination of the Neutron of both isotopes. This is illustrated below.
For isotope y xA:
Mass number = y
Atomic number = x
Neutron =..?
Atomic number = proton number = x
Mass number = Proton + Neutron
y = x + Neutron
Rearrange
Neutron = y – x
For isotope (y + 1) xA:
Mass number = y + 1
Atomic number = x
Neutron =.?
Atomic number = proton number = x
Mass number = Proton + Neutron
y + 1 = x + Neutron
Rearrange
Neutron = y + 1 – x
Step 2:
Determination of the difference between the neutron number of both isotopes. This is illustrated below:
For isotope y xA:
Neutron number = y – x
For isotope (y + 1) xA:
Neutron number = y + 1 – x
Difference in neutron number
=> (y + 1 – x) – (y – x)
=> y + 1 – x – y + x
Rearrange
=> y – y + 1 – x + x
=> 1
Therefore, the difference in the neutron number of both isotopes is 1
