Answer:
add a subscript of 4 after the O
Explanation:
The chemical formula of a compound is said to contain the elements in that compound with the respective number of atoms in each element. When writing chemical formula of a compound, the chemical symbols of each comprising element must be known. In this case involving Phosphorus tetraoxide, the symbols of the elements in this compound has been identified as P for Phosphorus and O for oxygen.
After identification of elemental symbols in the compound, Sebastian must now allocate the number of atoms that each element contains. According to the name of the compound, TETRA preceding oxygen means four (4), hence, four will be added as a subscript to O. Hence, at the end, the chemical formula will be PO4.
Please note that, the order of the chemical formula will go as the name implies Phosphorus tetraoxide, so phosphorus symbol (P) comes first, followed by oxygen symbol (O)
