Question

How is the radioactive decay of krypton-85 different from the radioactive decay of Americium-241?

Answer 1

Hint: The krypton-85 and Americium-241 are the isotopes of the atom krypton and americium. The isotopes are defined as the species where the atomic number is the same but the mass number is different. The unstable isotope undergoes radioactive decay to form another.

Complete step by step answer:
Marie Curie was the first person to coin the term radioactivity and after her Ernest Rutherford from his gold foil experiment investigated and named the three types of radiation.
The radioactive decay is defined as the spontaneous change of an unstable nuclide into another. The unstable nuclide is known as the parent nuclide and the nuclide which is formed from the decay is known as the daughter nuclide.
The experiment done by Ernest Rutherford involves the interaction of the radiation with magnetic and electric fields which help to determine the type of radiation containing positive charge $\alpha $-particles, negatively charge $\beta $-particles and neutral charge $\gamma $-particles.
The stability of the nucleus depends on the number of protons and neutrons. The ratio is given as $\dfrac{n}{p}$
When the $\dfrac{n}{p}$ratio is low( neutrons are less) then the nucleus will decay by $\beta $-decay.
When the $\dfrac{n}{p}$ratio is high( neutrons are high) then the nucleus will decay by $\alpha $-decay.
krypton-85, the isotope is written as ${}_{36}^{85}Kr$.
The number of protons is 36 and the number of neutrons is 49.
The $\dfrac{n}{p}$ratio is,
$ \Rightarrow \dfrac{{49}}{{36}}$
$ \Rightarrow 1.36$
The stable value is closer to 1.3, so Kr-85 decay by $\beta $-emission.
Americium-241, the isotope is written as ${}_{95}^{241}Pu$
The number of protons is 95 and the number of neutrons is 146.
The nucleus containing more than 82 protons is radioactive in nature. The ${}_{95}^{241}Pu$ decay by emission of $\alpha $-particles.

Note:
The mass number is the sum of the number of protons and number of neutrons. The number of neutrons is calculated by subtracting the mass number with the number of protons.