Question

$S^{-2}$ is isoelectronics with $x^{+2}$. If an atom of x contain $(z+2)$ neutrons then find no. of $e^{-}$, $p$ and $n$ in $x$ and $x^{+2}$. ($z=$Atomic no)

Answer 1

$x^{+2}$ is isoelectronic with $S^{-2}$

Number of electrons in $S^{-2}=16+2=18e^{-}$

$\therefore x^{+2}$ has $18e^{-}$ $\therefore x$ has $18+2=20e^{-}$

Given $x$ has $(z+2)$ neutrons

$z$ = Atomic number= Number of protons

=Number of electrons

$\therefore x$ has $20+2=22$ neutrons, $20$ electrons & $20$ protons.

And $x^{+2}$ has= $22$ neutrons, $18$ electrons & $20$ protons.