\(a.\left\{{}\begin{matrix}P+N+E=116\\P=E\\\left(P+E\right)-N=24\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}2P+N=116\\2P-N=24\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}P=N=Z=35\\N=46\end{matrix}\right.\\ b.NTK_B=46+35=81\left(đ.v.C\right)\\ m_B=81.0,16605.10^{-23}=13,45005.10^{-23}\left(g\right)\)