Question

If mass of one atom is $3.32\times {10}^{-23}g$, then calculate number of nucleons (neutrons and protons) present in $2$ atoms of the element.

• A. $40$
• B. $20$
• C. $10$
• D. $40N_A$

Answer 1

The correct option is A $40$

Number of nucleon =$\frac{Massofatom}{Molarmassofnucleon}=\frac{3.32\times {10}^{-23}g}{1.6726\times {10}^{-24}g/nucleon}=19.8=20\left(approximately\right)$

It is given that element comprises of 2 atoms

Hence,number of nucleon = $2\times 20=40$