Question

An atom of radium combines with two atoms of chlorine to form $RaC{l}_2$ molecule. The radioactivity of $RaC{l}_2$ will be :

• A. zero
• B. one-half of the same quantity of Ra
• C. one-third of the same quantity of Ra
• D. as much as that of the same quantity of Ra

Answer 1

Answer: (D)

as much as that of the same quantity of Ra

In any atom, protons and neutrons are packed together in a very small space in the nucleus.

• There must be some force of attraction between these particles to maintain the existence of nucleus.
• The columbic force of attraction is not enough to hold many particles in such a small space, as the repulsion force between protons would render the nucleus highly unstable and tend to disintegration.
• Hence, the force of attraction between nucleons which is stronger than the repulsive force between protons is called as nuclear forces.
• Nuclear forces operate within a small distance around 0.10 fermi only.

Those nucleus with n/p ratio one is highly stable. Elements with high n/p ratio are unstable an radioactive in nature. Elements till atomic number 20 are stable with n/p =1, as atomic number increases, n/p ratio increases and instability increases.
As radioactivity is characteristic property of unstable nucleus (here Ra) so it will remain same in both.