what is the atomicity of phosphorous?and valency?
Atomicity is the number of atoms of an element present in one molecule of that element. For example, there are 2 atoms of hydrogen present in H2 molecule. So its atomicity is 2.
The number of atoms present in a molecule of phosphorus are 4. So the atomicity of phosphorus is 4. Also, phosphorus shows two valencies - 3 and 5. For example, in P2O3, phosphorus shows a valency of 3, while in PCl5, it shows a valency of 5.