Question

nomenclature of covalent compounds
quiz complete
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which is the correct formula for phosphorus pentachloride?
○ pcl4 because a subscript of 4 indicates four cl atoms
○ pcl5 because a subscript of 5 indicates five cl atoms
○ p5cl because a subscript of 5 indicates five p atoms
○ p5cl3 because a subscript of 5 indicates five p atoms

Explanation:

P, "chloride" = Cl.

Step2: Match name to formula

Phosphorus pentachloride means 1 P atom and 5 Cl atoms, so formula is $\text{PCl}_5$.

Step3: Evaluate options

Only the second option correctly links the prefix "penta-" to 5 Cl atoms in $\text{PCl}_5$.

Answer:

P, "chloride" = Cl.

Step2: Match name to formula

Phosphorus pentachloride means 1 P atom and 5 Cl atoms, so formula is $\text{PCl}_5$.

Step3: Evaluate options

Only the second option correctly links the prefix "penta-" to 5 Cl atoms in $\text{PCl}_5$.