Final answer:
Lithium and oxygen form an ionic compound called lithium oxide (Li2O) through the transfer of electrons from lithium to oxygen, which results in the formation of Li+ and O2- ions held together by ionic bonds.
Step-by-step explanation:
When lithium (Li) and oxygen (O) bond together, they typically form an ionic compound. Lithium has a single valence electron in its 2s orbital, whereas oxygen has six valence electrons, needing two more electrons to fill its valence shell. Given that oxygen is more electronegative, it has a stronger tendency to attract electrons. Lithium, being less electronegative, can give up its single valence electron.
This transfer turns lithium into a Li+ ion and, as oxygen gains two electrons, it becomes an O2- ion. Consequently, the Li+ and O2- ions are held together by the strong electrostatic forces of attraction between particles with opposite charges, known as an ionic bond. Therefore, lithium and oxygen would form the ionic compound lithium oxide (Li2O).
In the context of molecules like lithium vapor or oxygen gas, these substances form through covalent bonding, such as O2 with a double covalent bond and Li2 with single covalent bonds between two lithium atoms. However, when discussing Li and O combining, it is the formation of an ionic compound rather than a molecular one.