`M_n` and `M_p` represent mass of neutron and proton respectively. If an element having atomic mass `M` has `N-`neutron and `Z`-proton, then the correct relation will be :

Options

A. `M lt [NM_n + ZM_p]`
B. `M gt [NM_n + ZM_p]`
C. `M = [NM_n + ZM_p]`
D. `M = N[M_n + M_p]`

Answer

A

Explanation

(a) Given, Mass of neutron = `M_n` mass of proton `= M_p` , atomic mass of the element `= M` , number of neutrons in the element `= N` and number of protons in the element `= Z`. We know that the atomic mass `(M)` of any stable nucleus is always less than the sum of the masses of the constituent particles.
Therefore, `M lt [NM_n + ZM_p]`.