The atomic numbers of elements X, Y and Z are | vedclass

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(C) The electronic configurations of the elements are as follows:For $X$ $(Z=19)$: $1s^2 2s^2 2p^6 3s^2 3p^6 4s^1$. The $M$-shell $(n=3)$ contains $2+

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$Z > Y > X$

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(C) The electronic configurations of the elements are as follows:For $X$ $(Z=19)$: $1s^2 2s^2 2p^6 3s^2 3p^6 4s^1$. The $M$-shell $(n=3)$ contains $2+6 = 8$ electrons.For $Y$ $(Z=21)$: $1s^2 2s^2 2p^6 3s^2 3p^6 3d^1 4s^2$. The $M$-shell $(n=3)$ contains $2+6+1 = 9$ electrons.For $Z$ $(Z=25)$: $1s^2 2s^2 2p^6 3s^2 3p^6 3d^5 4s^2$. The $M$-shell $(n=3)$ contains $2+6+5 = 13$ electrons.Comparing the number of electrons in the $M$-shell: $Z (13) > Y (9) > X (8)$.Thus, the correct order is $Z > Y > X$.

The atomic numbers of elements $X, Y$ and $Z$ are $19, 21$ and $25$ respectively. The number of electrons present in the $M$-shell of these elements follow the order:

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