Which of the following does not increase regularly?

Options

(a) mass number
(b) atomic number
(c) packing fraction
(d) binding energy

Correct Answer:

packing fraction

Explanation:

Mass number, atomic number and binding energy increases regularly whereas packing fraction does not increase regularly. Packing fraction (f) is the difference between the exact nuclear mass M of a nucleus and its mass number A, divided by the mass number and it is given by f = (M – A) / A The curve of f × 10⁴ against A shows a minimum at about A = 50, the packing fraction is negative for mass numbers between 16 and 180 and packing fraction is positive for mass number 16 > A > 180