Question

Please be thorough and clear in your response.

a) Draw the Lewis Structure for C₂H_6.

b) What's its electronic geometry?

c) Molecular geometry?

d) Hybridization of each carbon?

e) Polar or nonpolar molecule?

f) Draw its 3-D representation.

Answer 1

a) The Lewis structure of C2H6

b) The electronic geometry is Tetrahedral. The carbon has 4 valence electrons and thus needs 4 more electrons from four hydrogen atoms to complete its octet. The hydrogen atoms are as far apart as possible at 109obond angle. This is tetrahedral geometry.

c) The molecular geometry of C2H6 ( ethane - an alkane ) with the skeletal structure o H3CCH3 is
that of Tetrahedral molecular geometry.

d) To find the hybridization of a central atom is basically (1) counting the number of valence electrons in the molecule, (2) draw the Lewis structure of the molecule, (3) count the number of electron groups (this includes lone pairs, free radicals, bonds, etc.), (4) determine the shape based on the number of electron groups, and (5) determine the hybridization based on the shape.

for C2H6 it is explain below,

1) There are 8 valence electrons on C and 6 valence electrons on H. The total number of valence electrons is 14.

2) CH3 : CH3

3) On both carbons, there are four electron groups around them (3 single bonds to H, one single bond to C)

4) The shape of both carbons is tetrahedral because it has 4 electron groups around it.

5) The hybridization is SP3.

Just remember this table:

2 electron groups = SP = Linear arrangement
3 electron groups = SP2 = Trigonal Planar arrangement
4 electron groups = SP3 = Tetrahedral arrangement
5 electron groups = SP3D = Trigonal Bipyramidal arrangement
6 electron groups = SP3D2 = Octahedral arrangement

e)The H3C-CH3 ethane molecule is symmetrical. The C-H bonds are polar, but the dipole moments in C2H6 cancel each other other due to its symmetry. As there is no nett dipole moment, ethane is nonpolar.

f) 3D Structure