Question

Mass of a nucleus of an atom is 3.87 x 10^-23. This nucleus contains 10 neutrons. Identify the element.

Answer 1

Mass of nucleus = $3.87 \times 10^{-23} g$

Mass of one neutron = $1.67 \times 10 ^{-24}$ g

Total mass of 10 neutron = $1.67 \times 10 ^{-23}$ g

Mass of nucleus = Z(mass of one proton) + (A-Z) mass of one neutron

$3.87 \times 10 ^{-23}= (Z\times 1.67 \times 10^{-24} )+ 1.67 \times 10 ^{-23}$

$Z =\frac{ 2.2\times 10 ^{-23}}{1.67 \times 10^-24}= 13$

So number of proton = 13

So , element is Aluminium.