Name:  __________________________
	Worksheet #5 Packet 1  2nd Qt.           Modern Atomic Theory Complete the following:           Subatomic      /     Location     /     Charge      /    Mass (amu)           Particle         ------------------------------------------------------------------------------------   1.    Proton             inside nucleus          1+                ?????   2.    Neutron                  ?????              ?????                 1   3.    Electron                 ?????                1-                    0   If the statement is true, write "true." If it is false, change the underlined word or words to make the statement true. Write your answer on the line provided.   ____________ 4. Moseley discovered that all atoms of an element have the same number of neutrons in their nuclei.   ____________ 5. In an individual, neutral atom, the number of protons always equals the number of electrons. ____________   6. When an atom loses or gains one or more electrons, it is called an ion.   ____________ 7. The average mass of an element's atoms is called the atomic number. ____________   8. 1 atomic mass unit (amu) is equal to 1/12 of the mass of a carbon-12 atom. ____________   9. Atoms with the same number of protons but different numbers of electrons are called isotopes.   Answer each of the questions in the space provided.   10. How do two istopes of oxygen, oxygen-16 and oxygen-18, differ from each other in structure?    __________________________________________________________   __________________________________________________________   11. How can you calculate the net charge of an ion if you know the number of protons, neutrons, and electrons it contains?   _________________________________________________________   _________________________________________________________     Calculating Atomic Mass Samples of an unknown element X were collected and their masses were recorded. Use the information given to answer the following questions.    Isotope      /  Mass (amu)    /   Percent Abundance    /   Mass Number     1                     37.765                         9.67                             ???     2                     39.056                       78.68                            ???     3                     40.003                       11.34                            ???     4                     41.060                         0.31                            ??? 12.. Fill in the mass number for each sample of element X in the data table. 13.. What is the most common isotope of element X? _________________ 14.  Calculate the average isotope of element X. 15.  Use your periodic table to identify element X based on it's average atomic mass. ___________________________ 16.  What is the atomic number of this element? _______________ 17.  Draw an atom of this element. Make sure to correctly represent the # of protons & neutrons in the atom.