Final answer:
The chemical formula for 'triantimony heptoxide' is Sb3O7, which includes three antimony atoms and seven oxygen atoms.
Step-by-step explanation:
The correct chemical formula for the covalent compound named triantimony heptoxide is derived by the combination of the prefixes 'tri-' and 'hepta-' which indicate the number of atoms of each element present in the compound, with 'tri-' meaning three and 'hepta-' meaning seven. Therefore, the correct chemical formula for triantimony heptoxide includes three antimony (Sb) atoms and seven oxygen (O) atoms; hence the formula is Sb3O7.