# How can anions exist?

Consider an nitrogen atom with 7 protons and 7 electrons. How can an nitrogen anion $$\ce{N^-}$$ exist? Shouldn't the 7 electrons in valence shell repel the extra one?

What force does hold the extra one electron in the valence shell? There isn't an extra proton in the $$\ce{N^-}$$ that would hold the extra electron.

• Note that nitrogen is, aside of noble gases, one of few elements ( also e.g. Be, Mg, Mn, Zn) with negative electron afinity, therefore energy is released by repulsion of the extra electron and such an anion can exist only for a minimal time period of the order of microseconds to milliseconds. May 31 at 9:08

The single anion $$\ce{N^-}$$ could exist, but would not be stable because it puts four electrons in the p shell. The p shell would prefer to have three electrons as it does in the nitrogen atom or no electrons as it does in the $$\ce{N^3+}$$ cation.