Question

Do electrons affect atomic mass?

Answer 1

1. The mass of an electron is $9.1093837\times {10}^{-31}$$\mathrm{Kg}$ and the mass of a proton is $1.67262192\times {10}^{-27}$ $\mathrm{Kg}$. This means that the mass of an electron is only $\frac{1}{1836}$ of the mass of a proton.
2. Mass of a neutron is $1.67493\times {10}^{-27}$ $\mathrm{Kg}$, which is again $1839$times the mass of an electron.
3. Since the mass of an electron is extremely less when we compared it with the mass of a proton and a neutron, we do not include the mass of an electron while calculating the atomic mass or mass number of an element.
4. So, no electron does not affect atomic mass.