Atomicity is the total number of atoms present in one molecule of an element or a substance.
P4​ contains 4 P atoms so its atomicity is 4.

Atomicity of P4 Molecules

Introduction

The atomicity of a molecule refers to the number of atoms that constitute the molecule. In the case of P4 molecules, the atomicity is 4, which means that each molecule is composed of four phosphorus (P) atoms.

Explanation

Phosphorus is a chemical element with the atomic number 15 and the symbol P. It exists in several different forms, including white phosphorus, red phosphorus, and black phosphorus. The atomicity of the P4 molecule specifically refers to the white phosphorus allotrope.

White Phosphorus

White phosphorus is a yellowish-white waxy solid that consists of individual P4 molecules. Each P4 molecule is composed of four phosphorus atoms arranged in a tetrahedral structure. The four phosphorus atoms are covalently bonded together, sharing electrons to form a stable molecule.

Covalent Bonding

Covalent bonding occurs when atoms share electrons to achieve a more stable electron configuration. In the case of P4 molecules, each phosphorus atom contributes one electron to form a covalent bond with each of the other three phosphorus atoms, resulting in a total of six shared electrons. This sharing of electrons creates a strong bond between the phosphorus atoms, holding the P4 molecule together.

Stability of P4 Molecules

The P4 molecules are highly stable due to the presence of strong covalent bonds between the phosphorus atoms. This stability is attributed to the octet rule, which states that atoms tend to gain, lose, or share electrons to achieve a stable electron configuration with eight valence electrons. In the case of P4 molecules, each phosphorus atom fulfills the octet rule by sharing electrons with the other three phosphorus atoms.

Conclusion

In summary, the atomicity of P4 molecules is 4, meaning that each molecule is composed of four phosphorus atoms. These atoms are covalently bonded together, sharing electrons to form a stable tetrahedral structure. The P4 molecules are highly stable due to the presence of strong covalent bonds, and this stability is attributed to the fulfillment of the octet rule by each phosphorus atom.