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Ta có: \(\left\{{}\begin{matrix}p+e+n=38\\p=e\\p+n-e=1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}p=e=18,5\\n=1\end{matrix}\right.\)
⇒ Sai đề
Số hạt không mang điện là: \(\left(38-1\right):2=18,5\) ( hạt)
Số hạt mang điện là: \(38-18,5=19,5\) ( hạt)
\(\Rightarrow p+e=19,5\)
Mà \(p=e\Rightarrow p=e=\dfrac{19,5}{2}=13\)
Vậy ..................
a,
Ta có: \(\left\{{}\begin{matrix}p+e+n=40\\p=e\\n-p=1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}3p=39\\n=p+1\\p=e\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}p=e=13\\n=14\end{matrix}\right.\)
b,
Ta có: \(\left\{{}\begin{matrix}p+e+n=21\\p=e\\p+e-n=7\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}2n=14\\p=e\\p+e+n=21\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}p=e=7\\n=7\end{matrix}\right.\)
c,
Ta có: \(\left\{{}\begin{matrix}p+n=16\\p=e\\\dfrac{p}{n}=\dfrac{1}{1}\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}2p=16\\p=e\\p=n\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}p=e=8\\n=8\end{matrix}\right.\)
Ta có: \(\left\{{}\begin{matrix}n+p+e=40\\n-p=1\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}n+2p=40\\n-p=1\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}n=14\\p=13\end{matrix}\right.\)
\(A=Z+n=13+14=27\)
=> X là Al
nbbnbnv ghvghgggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg
a) Ta có : \(\left\{{}\begin{matrix}2Z=18\\2Z=2N\end{matrix}\right.\)
=> Z=N=9
Vậy X là Flo (F)
b) Ta có : \(\left\{{}\begin{matrix}2Z+N=156\\2Z-N=32\end{matrix}\right.\)
=>\(\left\{{}\begin{matrix}Z=47=P=E\\N=62\end{matrix}\right.\)
A=Z+N=47+62=109
Ta có: p + e + n = 43
Mà p = e, nên: 2p + n = 43 (1)
Theo đề, ta có: n - p = 1 (2)
Từ (1) và (2), ta có HPT:
\(\left\{{}\begin{matrix}2p+n=43\\n-p=1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}2p+n=43\\-p+n=1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}3p=42\\n-p=1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}p=14\\n=15\end{matrix}\right.\)
Vậy p = e = 14 hạt, n = 15 hạt.