In a polar reaction mechanism, the atom that gives away electrons in a neutral nucleophile will end up as a(n):

The question is incomplete, the complete question is shown in the image attached.

Cation

Explanation:

In a polar reaction mechanism, a specie must give out electrons and another specie must accept those electrons.

The specie that gives out electrons becomes electron deficient and positively charged so we refer to such a specie as a cation.

Hence, the specie that looses electrons becomes a cation.

increased stability in the completion of fluorine's outer shell.