Answer
The number 4 behind P indicates that there are 4 individual atoms of Phosphorus. $P_{4}$ implies that it is a phosphorus molecule with 4 phosphorus atoms bonded together.
Work Step by Step
The number 4 behind P indicates that there are 4 individual atoms of Phosphorus. $P_{4}$ implies that it is a phosphorus molecule with 4 phosphorus atoms bonded together.