# Is the mass of a proton about the same as the mass of an electron?

The mass of a proton, fundamental, positively charged nuclear particles is approx. $1.67 \times {10}^{-} 27 \cdot k g$. On the other hand, the rest mass of an electron is approx. $9.11 \times {10}^{-} 31 \cdot k g$.