# How am I supposed to answer this? [closed]

First the question gives no units or that these are covalent radii or what, so I assume they are in nanometers and assume an atomic radius. I check my periodic table app and it says a 92pm atomic radius, 75pm covalent and 155pm van der waal for the N atom, which happens to be the first option I crossed out. Now what? BTW, this question is from a previous national aptitude test.

• If you remove the outermost electrons to give the ion do you think the atomic radius goes up or down? – Waylander Oct 24 '18 at 17:12
• In problems with self-contained data you should look for consistency, not "truth." – MaxW Oct 24 '18 at 19:07
• @Waylander of course the radius goes down, even I know that. But the question asks about adding electrons not removing them. – Sillysack Buttowski Oct 26 '18 at 7:57

• But I don't know the size of the $\ce{N-3}$ ion. – Sillysack Buttowski Oct 26 '18 at 7:53