Q97
General ScienceChemistry
$Mg^{2+}$ is isoelectronic with
- a.$Ca^{2+}$
- b.$Na^{+}$
- c.$Zn^{2+}$
- d.$Cu^{-}$
Answer: (B) $Na^{+}$
$Mg^{2+}$ has atomic number 12 minus 2 electrons = 10 electrons. $Na^{+}$ has atomic number 11 minus 1 electron = 10 electrons. Isoelectronic species have the same number of electrons. Both $Mg^{2+}$ and $Na^{+}$ have 10 electrons, making them isoelectronic (like the neon configuration).