Fill in the blank in each of the following nuclear equations. You will need to enter either a form of radiation or an isotope. If it is the latter, you must fully identify the isotope in superscript/subscript notation?

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1 Answer
Jun 1, 2018

A. color(white)(l)_10^(23)"Ne" to color(white)(l)_11^(23)"Na" + e^-

B. color(white)(l)_94^(242)"Pu" to color(white)(l)_2^(4)"He" + color(white)(l)_92^(238)"U"

C. color(white)(l)_84^(204)"Po" + e^(-) to color(white)(l)_83^(204)"Pb"

Explanation:

Equation A describes a neon-23 atom undergoing radioactive decay; a sodium atom of the same mass number A=23 is formed as the product; however the proton number Z decrease by 1. A drop in Z without any changes in A indicates that some weak interactions must have been taken place.

The beta-plus decay process, in which a neutron converts to a proton while emitting an electron, is likely to be accountable for this observation:

color(white)(l)_0^(1)"n"^0 to color(white)(l)_1^(1)"p"^+ + e^(-)

Optional: Check for the conservation of charge in this equation:

"L.H.S."=0=1+(-1)="R.H.S."

Note that this problem does not state the charge on each of the species. It is, therefore, necessary to check A and Z numbers when completing the equation.

color(white)(l)_10^(23)"Ne" to color(white)(l)_11^(23)"Na" + ul(color(black)("x"))

"x" should carry a nucleon number of 0 and a baryon number of -1; what is x?

In the second equation B., plutonium 242 undergoes alpha decay and emits an alpha particle (helium 4 nucleus color(white)(l)_color(purple)(2)^color(navy)(4)"He".) As a result, the "A" number of the product nuclei shall be lower than the parent nuclei by color(navy)(4) and the "Z" number lower by color(purple)(2).

color(white)(l)_94^(242)"Pu" to color(white)(l)_2^(4)"He" + color(white)(l)_92^(238)"X"

The product should, therefore, contain 238 nucleons and 92 protons. What is the symbol for this element?

In the third equation C., polonium 204 undergoes electron capture to convert a proton into a neutron.

color(white)(l)_1^(1)"p"^(+) + e^(-) to color(white)(l)_0^(1)"n"^0

... which is nearly the same as the beta decay process, reversed. As a weak interaction process, the nucleon number of the product will be identical to that of the parent nuclei; the proton number, however, will decrease by 1 as one of the protons got converted to a neutron.

color(white)(l)_84^(204)"Po" + e^(-) to color(white)(l)_color(purple)(83)^(204)"X"

which element does "X" represent?