Which ion is formed when an atom of fluorine (F) gains one electron

fluoride ion

Explanation:

If atoms gain electrons, they become negative ions, or anions. Consider the example of fluorine (see Figure below). A fluorine atom has nine protons and nine electrons, so it is electrically neutral. If a fluorine atom gains an electron, it becomes a fluoride ion with an electric charge of -1.

hope that helps!

all eukaryotic cell have mitochondria : )

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

if you need further assistance, let me know: )

~ trueboss72