Quick Ionization Energy Problem

[thejamespark]

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So I just wanted solidify my thought process.
Rank the following in terms of increasing first ionization energy.
F, N, K, Cs

Answer: Cs < K < N < F

True the trend is bottom left to top right but I was a little skeptical about at first because N has 3 valence electrons in the 3P orbital and is in a 'somewhat' stable state compared to lets say Carbon (2 electrons in the 3P orbital). So wouldn't it have a higher ionization energy against F?

Basically.... Cs < K < F < N so... why not this???
Just need to verify this thought.

 

[Saiph]

Flourine has 7 valence and would not want to give any electrons away. 1st Ionization energy is the energy required to remove one/first electron. So Nitrogen having 5 would not care as much about losing an electron than Flourine.