## Chemistry: The Science in Context (4th Edition)

(a) SO (b) SO$_{2}$ (c) SO$_{3}$ (d) S$_{2}$O (e) S$_{6}$O (f) S$_{7}$O
We keep in mind that if the first element does not have a prefix, that means that there is only one atom of this element in the compound. To write molecular formulas for these compounds, we must familiarize ourselves with the different prefixes indicating how many of each atom is present in the compound. For example, "$mono-$" means "one," "$di-$" means "two," "$tri-$" means "three," "$tetra-$" means "four," "$penta-$" means "five," "$hexa-$" means "six," and "$hepta-$" means "seven." (a) The name of this compound indicates that there is one atom of sulfur bonded to one atom of oxygen, so this compound's molecular formula is SO. (b) The name of this compound indicates that there is one atom of sulfur bonded to two atoms of oxygen, so this compound's molecular formula is SO$_{2}$. (c) The name of this compound indicates that there is one atom of sulfur bonded to three atoms of oxygen, so this compound's molecular formula is SO$_{3}$. (d) The name of this compound indicates that there are two atoms of sulfur bonded to one atom of oxygen, so this compound's molecular formula is S$_{2}$O. (e) The name of this compound indicates that there are six atoms of sulfur bonded to one atom of oxygen, so this compound's molecular formula is S$_{6}$O. (f) The name of this compound indicates that there are six atoms of sulfur bonded to one atom of oxygen, so this compound's molecular formula is S$_{7}$O.