[Shadow]

Why isn't boron more electronegative than fluorine? It's 2p orbital is lower in energy than the 2p orbital of fluorine meaning that it should be more electronegative .

[narutoverse13]

Fluorine is the most electronegative element. Electronegativity increases as you go right and up the periodic table. The exception to this is obviously the noble gases who have a complete ring of electrons around them. Flourine is the element who is the most to the right and up on the periodic table. Take a look at the picture I uploaded.

[Borek]

Why isn't boron more electronegative than fluorine? It's 2p orbital is lower in energy than the 2p orbital of fluorine meaning that it should be more electronegative .

I am not sure where your question comes from. Most commonly used electronegativity scale (Pauling) doesn't care about energy of orbitals in atoms - it is calculated using bond dissociation energies.

[Shadow]

That's the MO theory explanation of electronegativity, but then I concluded that boron is more electronegative than fluorine. The lower the atomic orbital in energy the bigger the electronegativity of an element. Where is the catch?