Order the following elements according to increasing size. My answer was Na+ Fe- Ne O2- Ne3- but I got this question wrong.

 Order the following elements according to increasing size.

  N3-   O2-   F-   Na+   Ne

Can someone please explain this to me. My answer was Na+ < Fe- < Ne < O2- < Ne3- but I got this question wrong. I thought that the more electrons the more difficult it is for the positive nucleus to hold them closer, meaning the elements would get bigger. But I got it wrong so there has to be something wrong with my logic.