Name:  __________________________
		4-4 Review and Reinforcement A New Approach to the Atom  On the line at the left, write the term from the list that matches each description below.  electron spin  quantum number  orbital  Pauli exclusion principle  electron density  principle energy levels  quantum-mechanical model  ___________________________________ 1. a region in space where an electron with a particular energy is likely to be found ___________________________________ 2. the density of an electron cloud ___________________________________ 3. number designating a principle energy level in an atom ___________________________________ 4. states that each orbital in an atom can hold at most two electrons and that these electrons must have opposite spins ___________________________________ 5. explains the properties of atoms by treating the electron as a wave and quantizing its energy ___________________________________ 6. the main energy levels in an atom ___________________________________ 7. the clockwise or counter clockwise motion of an electron  On the line at the left, write the letter of the answer that best completes each statement.  ___________ 8. The electron cloud is least dense where the probability of finding an electron is                          a. greatest.                          b. lowest.                          c. highly likely.                          d. nonexistent. ___________ 9. The first principle energy level of the hydrogen atom contains only a(n)                         a. s orbital.                         b. p orbital.                         c. d orbital.                         d. f orbital. ___________ 10. All p orbitals are shaped like                           a. spheres.                           b. doughnuts.                           c. dumbbells.                           d. footballs. ___________ 11. The 3s orbital differs from the 2s orbital in that it is                             a. smaller.                             b. larger.                             c. a different shape.                             d. more crowded. ___________ 12. The number of sublevels in eahc principle energy level equals the                               a. mass of the atom.                               b. electron density of the atom.                               c. quantum number for that energy level                               d. number of electrons in the atom. ___________ 13. Which sublelvels can be found in the fourth principle energy level of an atom?                           a. s and p                           b. s, p, and d                           c. s, p, d, and f                           d. s, p, d, f, and g
	14. How does the quantum-mechanical model of the atom describe electrons?     _______________________________________________________________________     _______________________________________________________________________     _______________________________________________________________________    ________________________________________________________________________    ________________________________________________________________________ 15. Explain the significance of drawing the 90 percent contour of orbitals.      _______________________________________________________________________      _______________________________________________________________________      _______________________________________________________________________      _______________________________________________________________________ Complete the chart below by filling in the correct number of orbitals and electrons in each sublevel.                 Sublevel                   Number of orbitals             Maximum number of orbitals 16.                s                      _________________________________________________ 17.                p                      _________________________________________________ 18.                d                      _________________________________________________ 19.                f                      _________________________________________________