Question

what is nucleons ?how many nucleons are present in phosphorus?

Answer 1

Nucleons refer to the  number of protons and neutrons present in an element.
The name " Nucleons" comes from the fact the species residing in the nucleus of the element.

Thus Nucleons = neutrons + protons,
Phosphorous has an atomic number 15.
The number of electrons = no.of protons = atomic number of the element
So the no.of protons in phosphorous =15
The mass number of Phosphorous = 31
So the no.of neutrons present in Phosphorous = 31-15 =16
Thus the no.of nucleons present in phosphorous = 15+16 =31

The atomic structure of phosphorous is at the top

Answer 2

Thus Nucleons = neutrons + protons,
Phosphorous has an atomic number 15.
The number of electrons = no.of protons = atomic number of the element
So the no.of protons in phosphorous =15
The mass number of Phosphorous = 31
So the no.of neutrons present in Phosphorous = 31-15 =16
Thus the no.of nucleons present in phosphorous = 15+16 =31