Central portion of the nucleus is positively charge.It consists of proton and neutron which are collectively called nucleons.Proton is positively charge particle while neutron is a neutral particle.Roughly both particles have same mass.Some of the properties of nucleus are as under

i)Nuclear Force

ii)Isotopes

iii)Nuclear Radi

iiv)Nuclear spin and magnetism

Nuclear Force:

     Nucleons held together inside the nucleus by means of strong short force known as nuclear force.The nuclear force is short range and is strong attractive force(it is only attractive).Its range is rougly equal to 10^-15m(10power-15)It is limited inside the nucleus onlyIn case of light nuclei,the hold of nuclear force is much greater,due to which the light nuclei has much greater stability.

     However for large size nuclei where some distance between the nucleon exists,the impact of the nuclear attractive force becomes weaker and the long range coloumb's repulsive force plays ts role effectively,thats why oftenly the heavy nuclei are unstable.

So,stability is due to short range force,and

unstability is due to long range force.Due to unstability,the nucleus can be easily broken into fission fragment with the emission of radiation.

Isotopes:

     Two nuclei with same atomic number but having different mass number are said to be isotopes.Isotopes of element have the same place in the periodic table.In isotopes,the number of protons and electrons are equal but number of neutrons are different.Example,Hydrogen has three isotopes protium,deutrium and tritium.

Nuclear Radii:

     The nucleus has not sharp and well defined surface.However,mostly the nucleides are spherical.We can estimate the effective radius of a nucleus by

R=R0(A)^1/3

R=effective radius

A=mass number

R0=constant and is equal to 1.2 femtometer

Nuclear Spin and magnetism:

     Nucleus has intrinsic angular momentum whose maximum component along any chosen z-axis is given by j(h/2pi) where j is quantum number and it may be integral or half integral,this is known as nuclear spin and also its nuclear magnetic moment is

 UN=eh/4(pi)mp

This expression is known as the nuclear magneton of the nucleus.

These are the some of the properties of the nucleus of an atom