UNIT 2 – SELF-TEST

Part 1:  Multiple Choice with explanation.

1. Which of the following correctly lists the particles, in order, from least massive to most massive?  (a) proton, electrons hydrogen atom, helium atom.  (b) proton, helium atom, hydrogen atom, electron.  (c) electron, proton, hydrogen atom, helium atom.   (d) hydrogen atom, electron, helium atom, proton
    

2. An atom of an element with atomic number 48 and mass number 120 contains:  (a) 48 protons, 48 electrons, and 72 neutrons.  (b) 72 protons, 48 electrons, and 48 neutrons.  (c) 120 protons, 48 electrons, and 72 neutrons.  (d) 72 protons, 72 electrons, and 48 neutrons.
    

3. Which symbol correctly represents an element (D) whose atoms contain 15 protons and 20 neutrons?  (a) ²⁰D   (b) ¹⁵D   (c) ³⁵D   (d) ¹⁵D
    

4. What is the maximum number of electrons allowed in the third principal energy level?  (a) 2,  (b) 8,  (c) 18,  (d) 32.
    

5. According to Hund’s rule, when electrons occupy orbitals of equal energy, one electron enters each orbit until:  (a) all the orbitals contain one electron, with spins parallel.  (b) all the orbitals contain one electron, with opposite spins.  (c) there are two electrons in each orbital.  (d) electron velocities become constant.
    

Part 2:  Short Answers and Problems:  Answer the following questions in the space provided.

6. Give four basic points of Dalton’s atomic theory.

7. Name an experiment and atomic model associated with these names: Thomson, Rutherford and Bohr.

8. (a) Write the nuclear equation for the a-particle decay of ²³⁸U
   
   (b)  Write the nuclear equation for the b-particle decay of ³⁸Cl.
    

9. Complete the following nuclear equations.
   
   ¹⁸⁵Au  -->  ____  +  ⁴He
   
   ¹n  +  ²³⁵U  ---->   ______   +  ⁹²Kr  +  3 ¹n
    

10. Give the electron configuration for the following elements:

(a) sulfur:
(b) zirconium:
(c) argon:

11.   Draw the orbital diagram for the following elements:

(a) boron:
(b) nitrogen:
(c) iron: (only 4s and 3d)

12.   For each group of sublevels, circle the one that fills last as electrons are added?

a.  3p 2p 1s 2s 3s        b.  4p 3p 2p 4s 4d 5s               c.  3d 4s 3p 3s 2s

13.   What is the maximum number of electrons in the:

a.  1st energy level _______   b.  3d orbital _____    c.  4p sub-level _______

14.   What is the element with the electron configuration or orbital diagram:

a.  1s² 2s² 2p⁶ 3s²

b.  hi  hi  hi hi hi  hi  h h h
      1s         2s                  2p                 3s                  3p

c.  [Ar] 4s¹ 3d¹⁰

d.  [Ar]  hi h h h h h
               4s                             3d

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