Atomicity of phosphorus is:

The formula of Phosphorus is P_4. So the atomicity of phosphorus is 4.

The number of atoms presents in a single molecule is termed its atomicity. It can be classified into three types.

The molecules of many elements are composed of only a single atom of that element. They are termed monatomic. For example, Ar (Argon), He(Helium). So their atomicity is one.
The molecules of many elements are composed of two atoms of that element. For example, oxygen can never exist independently and exist as an O₂ molecule known as diatomic, So its atomicity is 2.
The molecules of many elements are composed of three atoms of that element. They are termed triatomic, For example, O₃, CO₂. So their atomicity is 3.
The molecules of many elements are composed of four atoms of that element. They are termed as tetra atomic For example, P₄, SO₃. So their atomicity is 4.

Related Questions & Answers
Which Allotrope Of Phosphorus Has A Higher Density	Answer In One Word Hormone That Triggers Puberty In Males Is Known As
What Are The Properties Of Ultraviolet Waves	Give An Example Where Tyndall Effect Can Be Observed
How Many Planets Does The Solar System Consist Of	Reaction Of Granulated Zinc With Dil Hcl Results In Formation Of
Where Are Genes Located	Which Hybridization Has The Maximum Bond Angle
What Is Electrolytic Cell Is Used To Convert	What Do You Understand By Soil Erosion