This is actually a multiple choice question.
Why is the first ionisation energy of neon higher than that of fluorine?
- A: Fluorine is more electronegative than neon
- B: Neon has a complete octet, but fluorine does not
- C: The atomic radius of fluorine is less than that of neon
- D: The nuclear charge in neon is greater than that in fluorine
I understand why A is incorrect and why B is correct. But I am confused about C and D. I did try to search online but my questions just increased.
Firstly, why is the atomic radius of fluorine less than that of neon? Both fluorine and neon are in the same period which means that they have the same amount of shells. Since the nuclear charge of neon is more, shouldn't the nucleus attract the electrons in the outer shells closer? Which would result in neon having a smaller atomic radius than fluorine. Secondly, according to a source, the largest factor is that the 2p sub shell in neon is full whereas in the fluorine it is not. They said that a full sub shell means that the atom is more stable which is the way neon has a higher first I.E. but since the 2p sub shell is full, wouldn't there be mutual repulsion?
I'm sorry if this is a lot, I'm trying to get a head start for my next education level and I cannot find any textbooks for that level's chemistry. I've been reading a summarized guide book and trying to do assessments whilst trying to find guides online as well.