Câu 5:
\(a,Z=P=E=15\left(hạt\right)\\ A=Z+N=15+16=31\left(đ.v.C\right)\\ \Rightarrow KH:^{31}_{15}P\\ b,Z^+=14^+\Rightarrow Z=P=E=14\\ A=Z+N=14+14=28\left(đ.v.C\right)\\ \Rightarrow KH:^{28}_{14}Si\\ c,A=Z+N=80\\ Mà:Z=35\\ \Rightarrow KH:^{80}_{35}Br\\ d,\\ \left\{{}\begin{matrix}P+E+Z=40\\\left(P+E\right)-Z=12\\P=E\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}2P+N=40\\2P-N=12\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}P=E=Z=13\\N=14\end{matrix}\right.\\ \Rightarrow A=Z+N=13+14=27\left(đ.v.C\right)\\ \Rightarrow KH:^{27}_{13}Al\\ e,\\ \left\{{}\begin{matrix}P+N=31\\N-P=1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}P=E=Z=15\\N=16\end{matrix}\right.\\ KH:^{31}_{15}P\)
