Answer the essay questions using complete sentences with correct grammar and spelling.
For full credit your answers must be well-organized, thorough, specific (not overly generalized) and precise (not vague.)
 

1. Name the following compounds:

a.) KHCO₃________________________________ c.) CuCl₂_________________________________b.) CaSO₄ _______________________________
 

2. Write the formulas:

    a.) Iron (III) Sulfide_____________________ c.) aluminum nitrite____________________b.) sodium hydroxide____________________
 
 

3. a.) Explain what the “Octet Rule” has to do with the formation of cations and anions.

Cations:

Anions:

4.     a.) Write the chemical formula for a compound composed of magnesium and chlorine.____________

       b.) Is the compound covalent or ionic?_________________ Explain your choice:
 
 

       c.) Draw Lewis dot diagrams for both individual atoms.
 
 
                                                 
 

5. a.) How can you tell if a covalent bond is polar or nonpolar?  
 
 
 

    b.) Give an example of each type of  bond:       Polar Covalent ______________        Nonpolar Covalent _______________
 

6. Fill in the following table:
                                                            CBr₄                                  OF₂                                 NO₃^-

Number of Valence electrons                 ______                                  _____                                   ______

_________________________________________________________________________________________
Lewis dot structure
 
 
 
 
 
 
 

____________________________________________________________________________________________
Number of e- pairs
around central atom
______________________________________________________________________________________________
Geometrical arrangement
of e- groups: name and
sketch
 
 
 
 
 
 
 

Shape of molecule: name
and sketch
 
 
 
 
 
 
 

_____________________________________________________________________________________
 

Polar or Nonpolar?                        _______                                 _______                              __________
_____________________________________________________________________________________
 

7. For the following two sets of elements:                                     a.) Na, Mg, K                 b.) S, Se, O
 

Which has the lowest electronegativity?                                             _______                     _________
Which of the three in a.) is most metallic?                                           ________
Which has the highest ionization energy?                                          ________                    ________
Which of the three in b.) is most nonmetallic?                                                                            ________
Which is the largest?                                                                              ________                     _________

8. Consider the element Phosphorus:

^{a.) It is in period_________ and Group_________.}

b.) How many valence electrons does this atom have?_________

c.) How many unpaired electrons does this atom have?________

d.) In order to achieve a stable octet this atom wants to __________(lose / gain) ________electrons.

9. Consider the element that has 2 electrons in the 1st shell, 8 in the 2nd shell, and 5 in the 3rd shell. How many valence electrons does this atom have?___

What Group is it in?_________  What period?________  When this atom forms an ion it will be an __________ (anion or a cation?) with a charge of __.

 This is an atom of  _________________ (name) ______ symbol.  Draw a Bohr Diagram for an excited state of this atom.

10. Answer the following questions for the compound ethanol, C₂H₆O. Units are important here!

a.) Is this compound ionic or covalent?_________________

b.) Do we refer to one atom, one molecule, or one formula unit of this compound?_____________

11. Name the following compounds:

        a.) N₂O₄ ______________________________  SF₆ _______________________________

Write formula for the following compounds:

a.) tetraphosphorus decoxide___________   b.) nitrogen tribromide ______________________________

 

12. Why is it incorrect to refer to a molecule of NaBr?

      What should one say instead?

 Ionic compounds do not exist as individual molecules like covalent compounds do. In what form do ionic compounds exist?

 Covalent compounds share electrons between the 2 atoms in a bond. What happens to electrons when an ionic bond is formed?

13. Give an example of a nonpolar covalent bond where the 2 atoms are different.___________ Give an example of a polar covalent

       bond______. Give an example of an ionic bond___________.

14. Draw the Lewis dot structures for CBr₄, PBr₃, and H₂S

  

 

 

    They all have the same electron pair geometry, namely  ________________________________.   But their shapes are all different.

     Name the shape of each molecule and the bond angle:  CBr₄_____________________________________ Br-C-Br bond angle____

                                                                                      PBr₃_____________________________________ Br-P-Br bond angle____

                                                                                       H₂S_____________________________________  H-S-H bond angle ____

    Explain your reasons for the bond angles you chose.

15. After class one day you saw the line spectra of excited hydrogen and helium atoms by looking through a diffraction grating in the darkened lab across the hall. What was going on within the atoms to produce the different line spectra for each?

 

 

 

16. When the electron in a H atom goes from the ground state to a higher energy level is energy absorbed or emitted? When an electron drops from a higher to a lower energy level is energy absorbed or emitted?

 

17. WorkPatch 4.5 was done in class. Be sure you understand how this was done!