What is the difference between an isotopic and isoelectronic species?

Isotopes are chemical species that have the same number of protons but a different number of neutrons as each other in their nuclei. For example, Deuterium (H²) and Tritium (H³) are isotopes of Hydrogen.Chemical species can be said to be isoelectronic when they have the same number of electrons, for example O^2- and F^- are isoelectronic ions as they both have 10 electrons. You can also have isoelectronic molecules, for example both N₂ and CO₂ have 14 electrons.