Deduce equations for the following nuclear reactions:

(i) Molybdenum-98 absorbs a neutron.

(ii) The isotope produced in (a) (i) decays into technetium-99m.

Molybdenum-99 has a half-life of 66 hours, while technetium-99m has a half-life of 6 hours. Outline why technetium-99m is made on-site.

Outline two reasons, other than its half-life, why technetium-99m is so useful in medical diagnosis.

Outline the nature of the radioactive waste that is generated by the use of technetium-99m in medical diagnosis.

i

\({}_{{\rm{42}}}^{98}{\rm{Mo}}\) + \({}_{{\rm{0}}}^{1}{\rm{n}}\) → \({}_{{\rm{42}}}^{99}{\rm{Mo}}\)

Accept ⁹⁸Mo + ¹n/n → ⁹⁹Mo.

ii

\({}_{42}^{99}{\text{Mo}} \to {}_{43}^{99\,{\text{m}}}{\text{Tc}} + {}_{ - 1}^0\beta \)

Accept “ \({}_{ - 1}^0e\)” for “ \({}_{ - 1}^0\beta \)”.

Accept “ \({}^{99}Mo \to {}_{}^{99\,{\text{m}}}Tc + \beta \)”.

Accept “ \({}_{ - 1}^0e/{e^ - }/e\)” for “\(\beta \)”.

Do not penalize “ \({}_{}^{99}Tc\)” for “ \({}_{}^{99\,{\text{m}}}Tc\)”.

molybdenum-99 can be easily transported «before it decays»/more stable
OR
«most of» technetium-99m will decay during transportation

Do not accept just “short half-life of Tc-99m”

emits gamma rays
OR
emissions escape from body
OR
emissions detected by gamma camera
OR
radiation dose is low

chemically reactive/versatile/transition metal bonds to a range of «biologically active» substances

Do not accept “short half-life of Tc-99m”.
Accept “energy of photons produced is «relatively» low” and “no high energy beta emission” for M1.
Accept “…has ability to form tracers” for “…bonds to a range of «biologically active» substances".

low-level «radioactive» waste/LLW
OR
small amounts of ionizing radiation for short time