Chapter 22.2, Problem 18LC

Interpretation Introduction

Interpretation: Electron dot structures of Ethene and Ethyne are to be drawn. Also, describe the shape of each molecule.

Concept Introduction: Electron dot structures are also called Lewis dot structures. Chemical bonding between atoms in a molecule is described diagrammatically. It also displays the total number of lone pairs present in each of the atoms constituting the molecule. The structure is made by following the Octet rule.

Answer to Problem 18LC

Electron dot structure of Ethene Electron dot structure of Ethyne

  

Shape of the Ethene molecule is Trigonal Planar.

Shape of the Ethylene molecule is Linear.

Explanation of Solution

Given Information: Shape of molecules Ethene and Ethyne depends upon bonding theories.

Electron dot structure of Ethene

Total number of valence electrons present are 12, the central atom is Carbon and Hydrogen is a side atom. Each Carbon has 4 valence electrons from where 2 electrons from each Carbon are used to make a double bond between them. Remaining 2 electrons of Carbon are used to make a total of 4 single bonds with 4 Hydrogen single atoms.

  

Electron dot structure of Ethyne

Total number of valence electrons present are 10, the central atom is Carbon and Hydrogen is a side atom. Each Carbon has 4 valence electrons from which 3 electrons from each Carbon is used to make a triple bond between them. Remaining 1 electron of Carbon is used to make a total of 2 single bonds with 2 Hydrogen single atoms.

  

Shape of the Ethene molecule is Trigonal Planar as we know Ethene has a formula CH₂=CH₂ where each Carbon is attached to 3 atoms- 2 Hydrogen and 1 Carbon forming the Trigonal planar shape.

Shape of the Ethyne molecule is Linear as all 4 atoms lie in a straight line.

Conclusion

Electron dot structure of Ethene Electron dot structure of Ethyne

  

Shape of the Ethene molecule is Trigonal Planar.

Shape of the Ethylene molecule is Linear.