From the following pairs of ions which one is not an iso-electronic pair ? (1) Fe2+, Mn2+ (2) O2−, F− (3) Na+, Mg2+ (4) Mn2+, Fe3+
Isoelectronic refers to two atoms, ions, or molecules that have the same number of total electrons and the same number of valence electrons. (a) O2− and F−both have 10 electrons (b) Na+and Mg2+ both have 10 electrons (c) Mn2+ and Fe3+ both have 23 electrons (d) Fe2+ has 24 electrons. Mn2+ has 23 electrons
