Question

The radius of germanium (Ge) nuclide is measured to be twice the radius of 94Be. The number of nucleons in Ge are :

• A. 73
• B. 74
• C. 76
• D. 72

Answer 1

Answer: (D)

72

Answer 2

The number of nucleons (protons and neutrons) in an element is determined by its atomic number (Z) and mass number (A).
The atomic number of germanium (Ge) is 32.
You need to know the atomic number of beryllium (Be) to compare.
Since the radius of Ge is measured to be twice that of Be, the number of nucleons in Ge is likely to be greater than Be.
Beryllium-9 (9Be) has 4 neutrons and 5 protons, so its mass number is 9.
Germanium-72 (72Ge) has an atomic number of 32, so its mass number is 72.
Therefore, the option is (D): 72.