Answer:
Noble gases. (Argon)
Step-by-step explanation:
Noble gases are found in the group eight element on the periodic table and are known for their inert nature.
Meaning that they don't react easily with other elements.
Phosphorus is a reactive element that when exposed to air (oxygen) catches fire.
If phosphorus is stored under Noble gases escpecially Argon it won't react with the surrounding air in the laboratory.