Question

Unstable substance exhibit high radioactivity due to:
A.low \[p/n\] ratio
B.high \[p/n\] Ratio
C.\[p/n\] = 1
D.none

Answer 1

Hint: We must know that the \[p/n\] ratio is the neutron–proton ratio of an atomic nucleus. It is the ratio of its number of neutrons to its number of protons. For naturally occurring atomic nuclei, this ratio typically increases with increasing atomic number.

Complete step by step answer:
Radioactivity is a feature of some unstable atoms to spontaneously emit nuclear radiation. These nuclear radiations are generally alpha particles or beta particles that are often accompanied by gamma-rays.
Such radiation is emitted when the nucleus undergoes radioactive decomposition and is converted into its different form. A radioactive atom will try to gain stability by ejecting protons or neutrons, as well as other particles, or by releasing energy through radiation.
When the atoms of an element have extra neutrons or protons in their nucleus, then it creates extra energy that causes the atom to become unbalanced or unstable.
 Nuclei having very high or low \[n/p\] typically undergo nuclear transformation. When \[n/p\] ratio is higher than required, the nuclei have the tendency to emit β rays whereas when \[n/p\] ratio is lower than the required stability, the nuclei either emits alpha particles or it will capture K-electron.
Thus, the unstable substance exhibits high radioactivity due to unbalance of protons and neutrons in the atom's nucleus or low \[p/n\] ratio or high \[n/p\] ratio.
Hence, the correct option is option A.
Additional information:
Radiation is the energy or the particles that are released during radioactive decomposition whereas the radioactivity of a material is the rate at which it emits radiation.


Note:
We must know that atoms available in nature are either stable or unstable. An atom is stable if their nucleus is balanced. An atom is unstable or radioactive if the nucleus is unbalanced. Unstable atom's nucleus results from an excess of either neutrons or protons.