1. Name the three fundamental particles found in atoms.  Give 
the electrical charges of each.  Which two have masses that are 
nearly equal and are much greater than the mass of the third ?  


               Proton  Neutron  Electron  

                                                                          
2. The atomic number gives the number of protons in the 
nucleus of an atom.  
                                                                          
3. The mass number gives the total number of protons and 
   neutrons in the nucleus of an atom.  
                                                                          
4. Atoms of an element which have different mass numbers are 
   called isotopes.  
                                                                          
5. Give an example of an element for which there is more than one 
   abundant isotope.  


                Cu, Cl, B, etc.  

                                                                          
6. Give an example of an element for which there is only one 
   abundant isotope.  


                C, N, O, Al, etc.  

                                                                          
7. How many protons, neutrons and electrons are in an atom of the 
most abundant isotope of each of the following elements ?  

 
            PROTONS  NEUTRONS  ELECTRONS  
                                                                          
    F           9          10           9 
                                                                          
    Au         79         118          79 
                                                                          
    Na         11          12          11 
                                                                          
    N           7           7           7 
                                                                          
    Al         13          14          13 
                                                                          
    U          92         146          92