Question

the formation of lithium fluoride (seen here) is due to
a a stronger pull by the lithium atom on its valence electron.
b increased stability in the completion of fluorines outer shell.
c the addition of an outer (higher) energy level in the fluoride ion.
d decreased attraction between the lithium and fluoride ions.

Explanation:

Lithium fluoride (LiF) is an ionic compound. Lithium (Li) has one valence electron and fluorine (F) has seven valence electrons. In ionic bonding, lithium donates its valence electron to fluorine. Fluorine, by gaining an electron, completes its outer shell (achieves an octet, which is a stable electron configuration).

• Option A: Lithium loses its valence electron, so it does not have a stronger pull on it (it gives it up).
• Option C: The fluoride ion (\(F^-\)) does not add a new outer (higher) energy level. It just fills the existing outer level (second energy level for F, which can hold 8 electrons).
• Option D: The attraction between lithium ion (\(Li^+\)) and fluoride ion (\(F^-\)) is what holds the ionic compound together (electrostatic attraction), so the attraction is not decreased.

Answer:

B. increased stability in the completion of fluorine’s outer shell