Here's why this is important:

* Electronegativity is a measure of an atom's ability to attract electrons towards itself when it is part of a chemical bond.

* High electronegativity means an atom has a strong pull on electrons.

Specifically, both fluorine and oxygen have a small atomic radius and a high number of protons in their nucleus.

* Small atomic radius: This means the electrons are closer to the nucleus, making the attraction stronger.

* High number of protons: This means the nucleus has a stronger positive charge, which attracts electrons more strongly.

These factors combine to make fluorine and oxygen highly electronegative, which is why they are often involved in polar bonds and can easily form anions.