1.___________ Another name for the nucleus is ____.
a. isotope c. nucleon
b. mass number d. nuclide
2. ___________ Atoms that have the same atomic numbers but different mass numbers are called ___.
a. isotopes c. nucleons
b. nuclei d. nuclides
3. ___________ Which of the following does NOT represent an isotope of tellurium?
a. 122 Te c. 128 Te
52 52
b. 124 Te d. 124 Te
52 53
4. ____________ The force of attraction among the particles in a nucleus that overcomes electrostatic repulsion and holds the nucleus together is the ___.
a. electrostatic force c. electromagnetic force
b. instability of the nucleus d. a mass defect
5. ____________ Which of the following does not occur when separated nucleons come together to form a nucleus?
a. the release of energy c. increased stability of the nucleus
b. instability of the nucleus d. a mass defect
Mark each statement T if it is true and F if it is fasle. For items 9-14, refer to Figure 18-5 Neutron-Proton Ratios of stable Nuclei on page 662 of the text.
6. ___________ Because a strong nuclear force of attraction holds nuclear particles together, a nucleus is at a lower energy state than are its separated nucleons.
7. ___________ The energy produced during the formation of a nucleus is very small compared with the energy changes that take place in ordinary chemical reactions.
8. ___________ During the formation of a nucleus, nuclear energy is produced at the expense of mass.
9. ____________ The graph in Figure 18-5 shows all 256 of the known stable nuclei represented by red dots that form a pattern called the band of stability.
10. ___________ Above atomic number 20, the most stable nuclides have more neutrons than protons.
11. ___________ Except for the smallest nuclei, all stable nuclei contain a number of neutrons that is equal to or greater than the number of protons.
12. ___________ Almost 90% of all stable nuclei have even number of protons and neutrons.
13. ___________ Nuclei with even numbers of protons and neutrons (and even-even combination) are particularly stable.
14. ___________ 16 O, 40 CA, and 88 Sr are nuclei with so-called magic numbers of nucleons
8 20 38
and tend to be very stable.
Complete each statement below by choosing a term from the following list. Use each term once.
decrease per nucleon less mole formed
nucleus maximum highest separate stable
protons matter repulsions mass number large
nuclear binding increase mass defect attraction
15. The _______________________ represents the amount of ___________________ converted into energy and released when a _______________________ is formed from protons and neutrons. Specifically, if one ___________________________ of 16 O nuclei were to be
8
________________________ from 8 mol of protons and 8 mol of neutrons, the resulting 1 mol of nuclei would have a mass that is 0.137005 g _______________________ than that of the original __________________________ and neutrons.
Stated differently, the ______________________ 1 mol of 16 O is the amount of energy
8
required to ____________________ 1 mol of 16 O nuclei into 8 mol of protons and 8 mole of
8
neutrons.
16. Figure 18-4 in the text shows a plot of average binding energy ____________________