Which of the following is not isoelectronic?

$({}_{32}Ge^{76}, {}_{34}Se^{76})$ and $({}_{14}Si^{30}, {}_{16}S^{32})$ are examples of

Which of the following are isoelectronic species?

The specific charge of a proton is $9.6 \times 10^7 \ C \ kg^{-1}$. What will be the specific charge for an $\alpha$-particle?

Two atoms of elements $X$ and $Y$ are isotones of each other. Their mass numbers are $70$ and $72$ respectively. If the atomic number of $X$ is $34$,then the atomic number of $Y$ is ..........

The number of electrons in $Cl^{-}$ ion is