Question

Bonding and Molecular Geometry

Pre-Laboratory Question

1. Most elements exist as components of compounds rather than in a free state. Explain why.

2. Use colored pencils to lightly shade each element in the Periodic Table of Electronegativity Values. Color 1 Color 2 Color 3 Color 4 0 – 0.9 1.0 – 1.9 2.0 – 2.9 3.0 – 4.0   Laboratory Questions

1. How does electronegativity influence the bond character between two elements?

2. Describe the conditions that make covalent compounds polar.

3. List the advantages of each type of model and the information that it provides and then list the limitations of that model. Molecular Formula Structural Formula Condensed Structural Formula Skeletal Model Ball-and-Stick Model Space-Filling Model

4. Both the alkene C4H8 and the alkyne C4H6 have rigid bond structures. However, C4H8 can form three isomers, whereas C4H6 can form only two isomers. Why is this so?  

5. Are these molecules isomers? Why or why not?

6. Which of the following molecules are geometric isomers, and which are structural isomers? Which molecule is in the trans position and which is in the cis position?

7. The skeletal model of benzene is often drawn like this:

Answer 1

1) most of the elements exist in compounds state like oxides , sulfides, sulphates because of the surrounding conditions and reactivitiy of the elements. only few elements occurs in free state those are Ag,Au,Pt.

2) Questions :

1) electronegativity difference between two elememts exceeds 1.9 the bond is ionic bond . less than 1.9 the bond is covalent bond

2) in covalently bonded atoms should have some electronegativity differece

suppose : HF, HCl, HBr H2O jn all these molecules the bond is polar covalent bond

4) C4H8 can show geometrical isomerism . thats why it can have totallly 3 isomers

a) 1-butene      b) cis-2-butente     c) trans-2-butene

   C4H6 can have only two isomers. no geometrical isomers are possible due to triple bond.

the isomers are: a) 1-butyne    b) 2-butyne

note : remaining questions are not clear 5,6,7 questions are here but no options and no molecules are given