An atom is supposed to be extremely small; a dot placed on paper with your pen has millions of them. Each atom has a central nucleus with electrons revolving around it. The nucleus is responsible for the weight of the atom. The size of the nucleus is, hundred thousand times smaller the atom itself which means the atom is made up of empty space.
Suppose 1 cm3 of space (the size of a medium seedless grape) is completely filled with neutrons no empty space at all. What will be the weight of such a 1 cm3 of neutrons?
Ans: Billions of tons. Surprised!!! It can be easily calculated. Try it.
The mass and the volume of a neutron is
Mass = 1.675 x 10-27 kg
volume = 1.881 x 10-44 m3
Using this, first find how many neutrons can fill 1 cm3 of space then multiply that number by the weight of a neutron. Try it yourself.