Question

part 3 of 4
phosphorus trifluoride:
part 4 of 4
sulfur trioxide:

Explanation:

To determine the chemical formulas for the given compounds:

Part 3: Phosphorus Trifluoride

Step 1: Identify the elements and their prefixes

Phosphorus (P) has no prefix, so there is 1 phosphorus atom. "Trifluoride" means 3 fluorine (F) atoms (prefix "tri-" indicates 3).

Step 2: Write the formula

Combine the symbols with the number of atoms as subscripts. So the formula is $PF_3$.

Part 4: Sulfur Trioxide

Step 1: Identify the elements and their prefixes

Sulfur (S) has no prefix, so 1 sulfur atom. "Trioxide" means 3 oxygen (O) atoms (prefix "tri-" indicates 3).

Step 2: Write the formula

Combine the symbols with the number of atoms as subscripts. So the formula is $SO_3$.

Answer:

s:
Part 3: $PF_3$
Part 4: $SO_3$