physchem 1 worksheet 008

8/11/2019 PhysChem 1 Worksheet 008

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STUDENT WORKSHEET OF PHYSICAL CHEMISTRY I: CHEMICAL STRUCTURE & BONDING

IGMA SANJAYA & DIAN NOVITA

PRINCIPLE OF CHEMICAL BONDING

Basic Competence : Understanding chemical bonding and its use for molecular

structure determination

Indicator : 1. To explain the basis of chemical bonding formation.

2. To describe the Born-Oppenheimer approximation in

explaining the formation of chemical bonding.

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WORKSHEET 008

1. a. Could you find the atoms H, O, Na, Al, and other atoms of non noble gases freely on our

earth? Give explanation for your answer!

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Could you find too the atoms He, Ne, Ar, and other atoms of noble gases freely on our

earth? Explain the reason of your answer!

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............................................................Based on above differences, explain why atoms of non noble gases tend to form chemical

bonds.

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b. Based on the literature, the formation of chemical bonding is related to energy stability.

To further clarify, draw the potential energy curve of a molecule. Complete the curve

with notation of the distance of separation between the two cores R, the equilibriumbond length Re, and the bond dissociation energy De. Then explain the meaning of the

curve.


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Fig. 1. a molecular potential energy curve.

The explanation of the curve:

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2. a. Are you able to find the molecular ion of ? In other words, is Hydrogen ion (proton)

to form a chemical bonding with another Hydrogen ion (proton) to form a molecular ion

of Explain why this might be happening!

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Are you able to find The molecular of . In other words, weather the hydrogen atom

tend to form a chemical bonding with another Hydrogen atom, explain the answer.

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Based on the above, please explain what caused the attractive forces of atoms in

chemical bonding.

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......................................................Based on this, try to predict whether you can make

-molecular ion. Then explain the

reason you thought so.

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3. a. Draw two thick black dots describing the position of proton A and proton B. Place a small

dot of electron in any place around the two thick black dots. When you drag a force line

from each protons to the electron, where the direction of motion of each proton relative

to one another.

Repeat this case by putting the electron in different locations, i.e. on the right location,on the left location, or in location between of the two protons.


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Describe where the location of electron so that their interactions caused both hydrogen

atom cores or protons move closer with each other.

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Summarize the position of electron density distribution in chemical bonding.

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4. a. Draw a chemical bonding model of hydrogen molecular ion with two thick black dots

mark each hydrogen nucleus A and B which is connected by the line R. Electron

positioned at the location between the two hydrogen nuclei which connected to point A

with rAline and to point B with rBline.

When a force drown from point A to the electron and also from point B towards the

electron, then explain what the point A (the core of the first hydrogen atom) and point B

(the core of the second hydrogen atom) will toward each other or away from each other.

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b. Write down in detail the Schrodinger equation to solve the case on the model 4.a.


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c. Explain why the equation resulting in 4.b. is difficult to be solved.

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d. Explain what Born-Oppenheimer assumed to resolve cases 4.a. which can be formulated

in the 4.b.

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e. What is the formulation of equation developed by Born-Oppenheimer as a result of the

simplification of the Schrodinger equation obtained from section 4.b.

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physchem 1 worksheet 008

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