Phosphorus is element number 15, with the symbol P. Its name comes from the Greek for “light-bearer.” It is also in phosphate, one of the three main fertilizer nutrients.
Atomic number 1530.97
PPhosphorusリン (rin)
Symbol
P
Atomic weight
30.97
Place in the table
Period 3 · Group 15
Atomic weight from the Chemical Society of Japan, “Table of Standard Atomic Weights with Four Significant Figures (2026)”.
The “light-bearer”
The symbol P comes from the Latin phosphorus, which combines the Greek words for “light” and “bearer.” The name comes from the way phosphorus gives off light.
Phosphorus was discovered in 1669, very early among the elements whose discovery year is known.
Helping flowers and fruit
The three main fertilizer nutrients are nitrogen, phosphate and potassium. Phosphate helps plants flower and bear fruit.
Phosphorus is in the third row of Group 15, directly below nitrogen. Two of the three fertilizer nutrients share one column.
Think about it
Q1If you were growing a vegetable we eat for its fruit, which fertilizer would you use more of?
Q2Look around you for things that glow in the dark.
Q3Do you think it is a coincidence that nitrogen and phosphorus share a column?
There is no single right answer. Talking it over with someone at home is a good way to learn.
Did you know? — Remember the three fertilizer nutrients this way: nitrogen for leaves, phosphate for flowers and fruit, potassium for roots.