# 11.4 Transmutation and nuclear energy  (Page 2/26)

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Prior to 1940, the heaviest-known element was uranium, whose atomic number is 92. Now, many artificial elements have been synthesized and isolated, including several on such a large scale that they have had a profound effect on society. One of these—element 93, neptunium (Np)—was first made in 1940 by McMillan and Abelson by bombarding uranium-238 with neutrons. The reaction creates unstable uranium-239, with a half-life of 23.5 minutes, which then decays into neptunium-239. Neptunium-239 is also radioactive, with a half-life of 2.36 days, and it decays into plutonium-239. The nuclear reactions are:

$\begin{array}{l}{}_{\phantom{\rule{0.5em}{0ex}}92}^{238}\text{U}+{}_{0}^{1}\text{n}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{}_{\phantom{\rule{0.5em}{0ex}}92}^{239}\text{U}\\ \\ \\ \phantom{\rule{2.2em}{0ex}}{}_{\phantom{\rule{0.5em}{0ex}}92}^{239}\text{U}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{}_{\phantom{\rule{0.5em}{0ex}}93}^{239}\text{Np}+{}_{-1}^{\phantom{\rule{0.5em}{0ex}}0}\text{e}{t}_{1\text{/}2}\phantom{\rule{4.9em}{0ex}}\text{half-life}=\text{23.5 min}\\ \phantom{\rule{1.7em}{0ex}}{}_{\phantom{\rule{0.5em}{0ex}}93}^{239}\text{Np}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{}_{\phantom{\rule{0.5em}{0ex}}94}^{239}\text{Pu}+{}_{-1}^{\phantom{\rule{0.5em}{0ex}}0}\text{e}{t}_{1\text{/}2}\phantom{\rule{5em}{0ex}}\text{half-life}=\text{2.36 days}\end{array}$

Plutonium is now mostly formed in nuclear reactors as a byproduct during the decay of uranium. Some of the neutrons that are released during U-235 decay combine with U-238 nuclei to form uranium-239; this undergoes β decay to form neptunium-239, which in turn undergoes β decay to form plutonium-239 as illustrated in the preceding three equations. It is possible to summarize these equations as:

${}_{\phantom{\rule{0.5em}{0ex}}92}^{238}\text{U}+{}_{0}^{1}\text{n}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{}_{\phantom{\rule{0.5em}{0ex}}92}^{239}\text{U}\phantom{\rule{0.2em}{0ex}}\stackrel{\phantom{\rule{0.4em}{0ex}}{\text{β}}^{\text{−}}\phantom{\rule{0.4em}{0ex}}}{\to }\phantom{\rule{0.2em}{0ex}}{}_{\phantom{\rule{0.5em}{0ex}}93}^{239}\text{Np}\phantom{\rule{0.2em}{0ex}}\stackrel{\phantom{\rule{0.4em}{0ex}}{\text{β}}^{\text{−}}\phantom{\rule{0.4em}{0ex}}}{\to }\phantom{\rule{0.2em}{0ex}}{}_{\phantom{\rule{0.5em}{0ex}}94}^{239}\text{Pu}$

Heavier isotopes of plutonium—Pu-240, Pu-241, and Pu-242—are also produced when lighter plutonium nuclei capture neutrons. Some of this highly radioactive plutonium is used to produce military weapons, and the rest presents a serious storage problem because they have half-lives from thousands to hundreds of thousands of years.

Although they have not been prepared in the same quantity as plutonium, many other synthetic nuclei have been produced. Nuclear medicine has developed from the ability to convert atoms of one type into other types of atoms. Radioactive isotopes of several dozen elements are currently used for medical applications. The radiation produced by their decay is used to image or treat various organs or portions of the body, among other uses.

The elements beyond element 92 (uranium) are called transuranium elements . As of this writing, 22 transuranium elements have been produced and officially recognized by IUPAC; several other elements have formation claims that are waiting for approval. Some of these elements are shown in [link] .

Preparation of Some of the Transuranium Elements
Name Symbol Atomic Number Reaction
americium Am 95 ${}_{\phantom{\rule{0.5em}{0ex}}94}^{239}\text{Pu}+{}_{0}^{1}\text{n}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{}_{\phantom{\rule{0.5em}{0ex}}95}^{240}\text{Am}+{}_{-1}^{\phantom{\rule{0.5em}{0ex}}0}\text{e}$
curium Cm 96 ${}_{\phantom{\rule{0.5em}{0ex}}94}^{239}\text{Pu}+{}_{2}^{4}\text{He}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{}_{\phantom{\rule{0.5em}{0ex}}96}^{242}\text{Cm}+{}_{0}^{1}\text{n}$
californium Cf 98 ${}_{\phantom{\rule{0.5em}{0ex}}96}^{242}\text{Cm}+{}_{2}^{4}\text{He}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{}_{\phantom{\rule{0.5em}{0ex}}97}^{243}\text{Bk}+2{}_{0}^{1}\text{n}$
einsteinium Es 99 ${}_{\phantom{\rule{0.5em}{0ex}}92}^{238}\text{U}+15{}_{0}^{1}\text{n}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{}_{\phantom{\rule{0.5em}{0ex}}99}^{253}\text{Es}+7{}_{-1}^{\phantom{\rule{0.5em}{0ex}}0}\text{e}$
mendelevium Md 101 ${}_{\phantom{\rule{0.5em}{0ex}}99}^{253}\text{Es}+{}_{2}^{4}\text{He}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{}_{101}^{256}\text{Md}+{}_{0}^{1}\text{n}$
nobelium No 102 ${}_{\phantom{\rule{0.5em}{0ex}}96}^{246}\text{Cm}+{}_{\phantom{\rule{0.5em}{0ex}}6}^{12}\text{C}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{}_{102}^{254}\text{No}+4{}_{0}^{1}\text{n}$
rutherfordium Rf 104 ${}_{\phantom{\rule{0.5em}{0ex}}98}^{249}\text{Cf}+{}_{\phantom{\rule{0.5em}{0ex}}6}^{12}\text{C}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{}_{104}^{257}\text{Rf}+4{}_{0}^{1}\text{n}$
seaborgium Sg 106 $\begin{array}{l}{}_{\phantom{\rule{0.5em}{0ex}}82}^{206}\text{Pb}+{}_{24}^{54}\text{Cr}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{}_{106}^{257}\text{Sg}+3{}_{0}^{1}\text{n}\\ {}_{\phantom{\rule{0.5em}{0ex}}98}^{249}\text{Cf}+{}_{\phantom{\rule{0.5em}{0ex}}8}^{18}\text{O}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{}_{106}^{263}\text{Sg}+4{}_{0}^{1}\text{n}\end{array}$
meitnerium Mt 107 ${}_{\phantom{\rule{0.5em}{0ex}}83}^{209}\text{Bi}+{}_{26}^{58}\text{Fe}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{}_{109}^{266}\text{Mt}+{}_{0}^{1}\text{n}$

## Nuclear fission

Many heavier elements with smaller binding energies per nucleon can decompose into more stable elements that have intermediate mass numbers and larger binding energies per nucleon—that is, mass numbers and binding energies per nucleon that are closer to the “peak” of the binding energy graph near 56 (see [link] ). Sometimes neutrons are also produced. This decomposition is called fission    , the breaking of a large nucleus into smaller pieces. The breaking is rather random with the formation of a large number of different products. Fission usually does not occur naturally, but is induced by bombardment with neutrons. The first reported nuclear fission occurred in 1939 when three German scientists, Lise Meitner, Otto Hahn, and Fritz Strassman, bombarded uranium-235 atoms with slow-moving neutrons that split the U-238 nuclei into smaller fragments that consisted of several neutrons and elements near the middle of the periodic table. Since then, fission has been observed in many other isotopes, including most actinide isotopes that have an odd number of neutrons. A typical nuclear fission reaction is shown in [link] .

what's the easiest and fastest way to the synthesize AgNP?
China
Cied
types of nano material
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
what is nanomaterials​ and their applications of sensors.
what is nano technology
what is system testing?
preparation of nanomaterial
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
what is system testing
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
can nanotechnology change the direction of the face of the world
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
how did you get the value of 2000N.What calculations are needed to arrive at it
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The eyes of some reptiles are sensitive to 850 nm light. If the minimum energy to trigger the receptor at this wavelength is 3.15 x 10-14 J, what is the minimum number of 850 nm photons that must hit the receptor in order for it to be triggered?
A teaspoon of the carbohydrate sucrose contains 16 calories, what is the mass of one teaspoo of sucrose if the average number of calories for carbohydrate is 4.1 calories/g?
4. On the basis of dipole moments and/or hydrogen bonding, explain in a qualitative way the differences in the boiling points of acetone (56.2 °C) and 1-propanol (97.4 °C), which have similar molar masses
Calculate the bond order for an ion with this configuration: (?2s)2(??2s)2(?2px)2(?2py,?2pz)4(??2py,??2pz)3
Which of the following will increase the percent of HF that is converted to the fluoride ion in water? (a) addition of NaOH (b) addition of HCl (c) addition of NaF