Which of the following is the correct chemical formula for phosphorus tribromide?

• A. P3Br
• B. PBr3
• C. Br3P2
• D. PB3

Answer: (B)

Verified step by step guidance

1. Understand the naming convention: 'Phosphorus tribromide' indicates a compound made of phosphorus (P) and bromine (Br) atoms, where 'tri-' means three bromine atoms are bonded to one phosphorus atom.
2. Recall that the chemical formula for a binary compound is written with the symbol of the element that comes first in the name first, followed by the other element. Here, phosphorus (P) comes before bromine (Br).
3. Use the prefix 'tri-' to determine the number of bromine atoms, which is 3, and since there is no prefix before phosphorus, it implies there is only 1 phosphorus atom.
4. Write the formula by placing the symbol for phosphorus first, followed by the symbol for bromine with the subscript 3 to indicate three bromine atoms: \(PBr_3\).
5. Verify that the formula matches the name: phosphorus tribromide corresponds to \(PBr_3\), which is the correct chemical formula.