Final answer:
The compound BaF2 is ionic, while SF4, PH3, and CH3OH are molecular.
Step-by-step explanation:
Out of the given compounds, BaF₂ and Na₂O would be expected to be ionic, while SF₄, PH₃, and CH₃OH would be molecular.
In an ionic compound, the atoms are held together by strong electrostatic forces between oppositely charged ions. In BaF₂, barium (Ba) loses two electrons to form a 2+ ion, while fluorine (F) gains one electron to form a 1- ion. This results in the formation of an ionic bond between Ba²+ and F⁻ ions.
In contrast, in molecular compounds, the atoms are held together by covalent bonds, which involve the sharing of electrons between atoms. SF₄, PH₃, and CH₃OH all involve covalent bonding between the atoms.