nuclear chemistry.....aim 3

what are natural and artificial transmutations? 

.....aim 2

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MU #1 Nuclear reactions include natural and artificial transmutation, fission, and fusion.

 

MU #2 Nuclear reactions can be represented by equations that include symbols which represent atomic nuclei (with the mass number and atomic number), subatomic particles (with mass number and charge), and/or emissions such as gamma radiation.

 

MU #3 A change in the nucleus of an atom that converts it from one element to another is called transmutation. This can occur naturally or can be induced by the bombardment of the nucleus by high-energy particles.

 

In natural transmutations the nucleus decays spontaneously. There is only one reactant or the nucleus that undergoes the transformation.

In order to balance nuclear reaction the total mass and total charge number of the reactants has to equal the total mass and total charge number of the products.

Example

The decay mode of gold-198 is β-  therefore, Au-198 transmutes naturally into Hg-198 by giving off a beta particle.

 

       

Example

The decay mode of Ca-37 is β+ therefore, Ca-37 transmutes naturally into K-37 by giving off a positron.

 

       

Example

The decay mode of Fr-220 is α therefore, Fr-220 transmutes naturally into At-216 by giving off an alpha particle.

   

       

Problem

Write the remaining natural transmutation nuclear reactions for radioisotopes in table N.                                      

 

In artificial transmutations the nucleus is bombarded with high-energy (kinetics energy) particles to induce transmutation. There are two reactants or the nucleus that is being bombarded and the high-energy particle.

 

Note: High-energy particles are accelerated in accelerators, by the application of electric and magnetic fields. Neutrons cannot be accelerated in accelerators using electric and magnetic fields because their charge is 0.

 

Example

The first artificial transmutation was accomplished in 1919 by Rutherford who bombarded nitrogen-14 with α particles.

 

           

Later, in 1930, Irene Curie and her husband Frederic bombarded stable Al-27 with alpha particles.

 

           

Problem

Find what X is in the following nuclear reactions.

 

            

 

           

 

           

 

             

TEST YOUR UNDERSTANDING

8/07

49 Which nuclear equation represents a natural transmutation?

 

82 Complete the nuclear equation for the decay of C-14. Your response must include the atomic number, the mass number, and the symbol of the missing particle.

6/07

Base your answers to questions 80 through 82 on the information below.

In living organisms, the ratio of the naturally occurring isotopes of carbon, C-12 to C-13 to C-14, is fairly consistent. When an organism such as a woolly mammoth died, it stopped taking in carbon, and the amount of C-14 present in the mammoth began to decrease. For example, one fossil of a woolly mammoth is found to

have 1/32 of the amount of C-14 found in a living organism.

80 Identify the type of nuclear reaction that caused the amount of C-14 in the woolly mammoth to decrease after the organism died.

81 Determine the total time that has elapsed since this woolly mammoth died.

82 State, in terms of subatomic particles, how an atom of C-13 is different from an atom of C-12.

1/07

50 Given the nuclear equation:

Which particle is represented by X?

6/02

The change that is undergone by an atom of an element made radioactive by bombardment with high-energy protons is called

            (1) natural transmutation            (2) artificial transmutation          (3) natural decay           (4) radioactive decay

8/02

1 Which reaction represents natural nuclear decay?

       

2 The spontaneous decay of an atom is called (1) ionization   (2) crystallization    (3) combustion  (4) transmutation

1/03 Which equation is an example of artificial transmutation?

8/03

33 Given the nuclear reaction:

 

This reaction is an example of (1) fission (2) fusion (3) artificial transmutation (4) natural transmutation

1/04

28 Which equation represents a spontaneous nuclear decay?
        (1) C + O2 ---> CO2  (2) H2CO3 ---> CO2 + H2O   (3) Al-27 + He-4 ---> P-30 + n   (4) Sr-90 ---> e- + Y-90

6/04

64 Given the nuclear equation: Cu-58 ---> Ni-58 + X     What nuclear particle is represented by X?

1/05

28 Which reaction is an example of natural transmutation?

50 Given the nuclear equation:

Which particle is represented by X?  (1) alpha (2) beta (3) neutron (4) positron

6/05

30 Which equation represents a transmutation reaction?

 

1/06

24 Positrons are spontaneously emitted from the nuclei of  (1) potassium-37 (2) radium-226 (3) nitrogen-16 (4) thorium-232

49 Given the nuclear equation:

6/06

27 According to Reference Table N, which pair of isotopes spontaneously decays?

        (1) C-12 and N-14 (2) C-12 and N-16 (3) C-14 and N-14 (4) C-14 and N-16

29 Which type of reaction converts one element to another element? (1) neutralization (2) polymerization (3) substitution (4) transmutation

8/06

28 Which notation of a radioisotope is correctly paired with the notation of its emission particle?

Base your answers to questions 64 and 65 on the information below.

A U-238 atom decays to a Pb-206 atom through a series of steps. Each point on the graph below represents a nuclide and each arrow represents a nuclear decay mode.

64 Based on this graph, what particle is emitted during the nuclear decay of a Po-218 atom?

65 Explain why the U-238 disintegration series ends with the nuclide Pb-206.

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