Fluorine lewis structures

[Colby Irvine 2A]

Hi, can someone help me understand how the electron affinity of fluorine would not let it form double bonds with Boron. Is that only for the example discussed in lecture, or does fluorine never form double or triple bonds?

[Grace Chen 3F]

I think it is because F's ionization energy is too high. If F forms double bond or triple bond, then the formal charge of F will be positive. Due to the high ionization energy (need huge amount of energy to remove e-), positive formal charge will be energy-wise inefficient and unstable.

[Omar Alkhalili 1J]

Hey! The octet rule tells us that atoms are stable when they have 8 electrons in their valence shell. That is the preferred condition of the atom. Fluorine has 7 valence electrons, so it only needs 1 electron to fill its shell. Hope that helps!

[Ashley Presnell 1C]

Since Fluorine is in group 17, it has 7 valence electrons and with its high electron affinity and ionization energy, it tends to want a -1 charge by gaining one more electron to have similar electron configuration to neon, a stable noble gas. Because of this, it would be hard to force Fluorine to form more than one bond because that is all it wants to do to become stable and lower its energy.

[Ruiyu Li 3I]

Because the formal charges of B and F are 0, we don't need to create a double bound. Also, because the ionization energy increase along the period and decreases along the group, F has very high ionization energy, which means it requires a large amount of energy to remove one e- from it. Creating a double bond would make F to have a positive charge, thus it's very unlikely to form a double bond.