Question

Write brief notes on the nucleus.

Answer 1

Nucleus: An atom consists of a heavy positively charged nucleus where all the protons and neutrons are present. Protons and neutrons are collectively referred to as nucleons.

Almost the whole mass of the atom is contributed by these nucleons. The magnitude of the positive charge on the nucleus is different for different atoms.

The volume of the nucleus is very small and is only a minute fraction of the total volume of the atom. The nucleus has a diameter of the order of 10^-12 to 10^-13 cm and the atom has a diameter of the order of 10^-8 cm.

$\frac{\mathrm{Diameter}\mathrm{of}\mathrm{the}\mathrm{atom}}{\mathrm{Diameter}\mathrm{of}\mathrm{the}\mathrm{nucleus}}=\frac{{10}^{-8}}{{10}^{-13}}={10}^5$

Thus, the diameter (size) of an atom is 100,000 times the diameter of the nucleus.

The radius of a nucleus is proportional to the cube root of the number of nucleons within it.
$\mathrm{R}={\mathrm{R}}_0.{\mathrm{A}}^{\frac{1}{3}}\mathrm{cm}$
where,

${\mathrm{R}}_0=1.33\times {10}^{-13}\mathrm{cm}$;

A = Mass number;

R = Radius of the nucleus.