When Plutonium-239 undergoes alpha decay, it becomes A) curium-241 + an alpha particle B) uranium-235 + an alpha particle C) neptunium-237 + and alpha particle D) plutonium-237 + and alpha particle
An alpha particle is composed of two protons and two electrons.
As a result, in alpha decay, the nucleus that decays loses two protons and two neutrons. So the mass number (239 in this case) decreases by 4.
239 - 4 = 235,
So the new nucleus must be B) Uranium-235, as it is the only one of the options that has an atomic mass of 235.
Answer:
The correct answer is option B.
Explanation:
Alpha decay: In this process, alpha particles is emitted when a heavier nuclei decays into lighter nuclei. The alpha particle released has a charge of +2 units.
The general alpha decay reaction is given as:
\(_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}\textrm{Y}+_2^4\alpha\)
So, when Pu-239 undergoes alpha decay it gives Uranium-235 and alpha particle.
\(_{94}^{239}\textrm{Pu}\rightarrow _{92}^{235}\textrm{U}+_2^4\alpha\)
Hence,the correct answer is option B.