In H-F bond formation, the fluorine atom completes its _ by acquiring a share of electron from hydrogen:

Explanation

Hydrogen, in its neutral state, has one electron in its 1s orbital. Fluorine, on the other hand, has seven electrons in its 2s and 2p orbitals and needs one more electron to achieve a stable, full valence shell. When hydrogen and fluorine come together, hydrogen donates its electron to fluorine, resulting in the formation of a hydride ion (H-) and a fluoride ion (F+). These ions are held together by electrostatic attraction, forming an ionic bond. So, in the context of H-F bond formation, the hydrogen atom donates its electron to fluorine, leading to the completion of fluorine's 2p orbital and the creation of ions rather than the sharing of electrons in a typical covalent bond.