Nidhi
Last Activity: 6 Years ago
Well, the correct order should be: Ne > F- > Na+
If you notice carefully all of these are isoelectronic species with a total of 10 electrons. Now, Ne is a noble gas therefore it’s radius is Van Der waal radius which is greater than ionic radius, so Ne has the greatest radius. Out of F- and Na+, since F gains one electron, the hold of F nucleus on outer shell electrons decreases per electron because the number of electrons in outer shell or the valence shell has increased, hence it expands whereas in case of Na, it loses 1 electron so the hold of nucleus on each outer shell electron increases (due to less outer shell electrons now) so it contracts which gives us this order.