CHAPTER 23 

                        (20 points)

1. (2 points) What is the meaning of the term "radioactive atom"?



2. (4 points) List four types of radioactive decay:



3. (3 points) Fill in the missing particle in the following equations:
  
   a.  23290Th ---> 23291Pa  +  _________________________________
                 
   b.  24395Am ---> 23993Np  +  _________________________________
        
   c.  20180Hg  +  _________________________________ ---> 20179Au
                                                
4. (4 points) Circle T (true) or F (false):
  
   a.  T   F  All elements with an atomic number greater than 83 are radioactive.
  
   b.  T   F  The faster neutrons travel, the more efficient they are in causing fission.
  
   c.  T   F  Cancer caused by exposure to radiation is an example of somatic damage.
  
   d.  T   F  One rad of alpha particles is more harmful than one rad of x-rays.

5. (4 points) An element has a half-life of 75.0 years.  If 100.0 g of the element were put 
              into a vault in 1950, how much of this element will remain in the year 2250?



6. (3 points) The nucleus of 56Fe has a mass of 55.92066 amu. 
              The sum of the masses of 30 neutrons and 26 protons is 56.44938 amu. 
              Explain:


			
              NUCLEAR CHEMISTRY PRACTICE QUIZ KEY

                         (20 points)

1. (2 points) What is the meaning of the term "radioactive atom"?

   A radioactive atom possesses a nucleus which is unstable.  It will spontaneously decay 
   by emitting particles and/or electro-magnetic radiation in order to become more stable.

2. (4 points) List four types of radioactive decay:
  
   a.  alpha emission   b.  beta emission   c.  gamma emission   d.  positron emission
  
3. (3 points) Fill in the missing particle in the following equations:
  
   a.  23290Th ---> 23291Pa  +  0-1e
                 
   b.  24395Am ---> 23993Np  +  42He
        
   c.  20180Hg  +  0-1e ----> 20179Au
 
4. (4 points) Circle T (true) or F (false):
  
   a.  T*  F  All elements with an atomic number greater than 83 are radioactive.
  
   b.  T   F* The faster neutrons travel, the more efficient they are in causing fission.
  
   c.  T*  F  Cancer caused by exposure to radiation is an example of somatic damage.
  
   d.  T   F* One rad of alpha particles is more harmful than one rad of x-rays.

5. (4 points) An element has a half-life of 75.0 years.  If 100.0 g of the element were put 
              into a vault in 1950, how much of this element will remain in the year 2250?

   2250 years-1950 years = 300 years = 4 half life periods
	
           t½          t½        t½          t½           

   100 g -----> 50 g -----> 25 -----> 12.5 -----> 6.25 g

6. (3 points) The nucleus of 56Fe has a mass of 55.92066 amu. 
              The sum of the masses of 30 neutrons and 26 protons is 56.44938 amu. 
              Explain:
   
   The mass difference is called the "mass defect" of the nucleus.     
   This apparent loss of mass shows up as energy according to the equation E = mc2. 
   If 30 neutrons and 26 protons were put together to form 56Fe, 
   this amount of energy would be liberated.  If the 56Fe nucleus were to be 
   broken apart into separate protons and neutrons, this energy would be needed to effect 
   separation.  If 56Fe were broken into smaller components, energy would have 
   to be converted to mass.  Do you think this reaction has occurred or been observed?