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Chemistry 30  Unit II  Nature of the Substance         Donkin

Each of these statements or questions is followed by four responses. Choose the correct response in each case.

1.  Chemical bonds are the result of...

    a) electron-electron repulsion
    b) proton - proton attractions
    c) attraction of an atom's nucleus for its valence electrons
    d) simultaneous attractions of shared electrons for two nuclei.

2.  An ionic bond is usually formed between...

    a) two nonmetals
    b) two metals
    c) a metal and a nonmetal
    d) a metalloid and a nonmetal

3.  What is the correct formula for the ionic compound formed when magnessium reacts with fluorine ?

    a) MgF    b)  Mg2F        c)  MgF2     d)  Mg2F3

4.  What is the formula of the ionic compound formed when element X  ( three valence electrons ) reacts
      with element Y ( six valence electrons )?

    a) X2Y        b) XY         c)  X2Y        d) X3Y2

5.  Which of the following is a property of ionic compounds?

    a)  Their solids conduct electricity.
    b)  They are usually gases or liquids at room temperature.
    c)  They have high melting points.
    d)  They are soft and waxy.

6.  Which of the following is a property of molecular compounds?

    a)  They have low boiling points.
    b)  They are hard and brittle.
    c)  Their molten state conducts electricity.
    d)  They have high melting points.



7.  Element X has an electronegativity of 3.5 and element Y has an electronegativity of 3.0.
     The most probable type of bond between X and Y is :

    a) nonpolar covalent
    b) polar covalent
    c) ionic
    d) unpredictable

8.  Which of the following contains an atom that does not obey the octet rule?

    a) MgO        b) IF5        c) CCl4        d)  KCl

9.  What is the predicted shape of PH3 ?

    a)  tetrahedral
    b)  trigonal planar
    c)  trigonal pyramidal
    d)  linear


10.  What is the predicted shape of HCN ?

    a)  trigonal pyramidal
    b)  trigonal planar
    c)  tetrahedral
    d)  linear


Part II   Nature of the Substance

Use the following compounds:   CrMo,  SiC,  BBr3,  Cl2,  NaI,  B,  Au,  Ne,  Ba,  PCl3

1.  Which are molecular in nature: __________________________________________________

2.  Which are ionic in nature: ______________________________________________________

3.  Which are solids at room temperature: _____________________________________________

4.  Which will readily dissolve in water: _______________________________________________

5.  Which are covalently bonded substances with high melting points: _________________________

6.  Which will conduct electricity in a solid state: ________________________________________
   Part III   Nature of the Substance

Lewis Dot Diagram

Vector Analysis

Molecular Shape

1. SeH2





2. CCl4


Part IV   Nature of the Substance


Electronegativity  Difference Calculation       


Orbital   Representation


Lewis Dot Diagram 


Name the Shape

1. silver (I) fluoride






2. iodine heptafluoride




Part IV   Nature of the Substance - Short Answer Questions

1. List three intermolecular forces and describe each.






2. Metallic compounds are held together with __________ bonds.
Explain how this type of bond is responsible for three of the properties belonging to metals.






BONUS Question: Br. HONClIF is used to remember diatomic elements.
Why are these elements diatomic and other not ?