Câu 1: thiếu dữ kiện
Câu 2:
Ta có: \(\left\{{}\begin{matrix}p+e+n=34\\p=e\\p+e=1,8333n\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}2,8333n=34\\p=e\\p+e+n=34\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}n=12\\p=e=11\end{matrix}\right.\)
\(\Rightarrow A=12+11=23\left(u\right)\)
\(KHNT:^{23}_{11}Na\)
Câu 3:
Ta có: \(\left\{{}\begin{matrix}p+e+n=82\\p=e\\p+e-n=22\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}2n=60\\p=e\\p+e+n=82\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}n=30\\p=e=26\end{matrix}\right.\)
\(\Rightarrow A=26+30=56\left(u\right)\)
\(KHNT:^{56}_{26}Fe\)
Câu 4:
Ta có: \(\left\{{}\begin{matrix}p+e+n=114\\p=e\\p+e-n=26\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}2n=88\\p=e\\p+e+n=114\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}n=44\\p=e=35\end{matrix}\right.\)
\(\Rightarrow A=35+44=79\left(u\right)\)
\(KHNT:^{79}_{35}Br\)
Câu 5:
Ta có: \(\left\{{}\begin{matrix}p+e+n=40\\p=e\\p+e-n=12\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}2n=28\\p=e\\p+e+n=40\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}n=14\\p=e=13\end{matrix}\right.\)
\(\Rightarrow A=13+14=27\left(u\right)\)
\(KHNT:^{27}_{13}Al\)
