bond lengths and strengths

Moderators: Chem_Mod, Chem_Admin

josephyim1L
Posts: 61
Joined: Fri Sep 28, 2018 12:15 am

bond lengths and strengths

Postby josephyim1L » Wed Nov 07, 2018 4:21 pm

Can someone explain to me why single bonds are weaker than double bonds which are weaker than triple bonds? Shouldn't single bonds be the strongest?

Kyle Golden Dis 2G
Posts: 67
Joined: Fri Sep 28, 2018 12:17 am

Re: bond lengths and strengths

Postby Kyle Golden Dis 2G » Wed Nov 07, 2018 4:31 pm

Single bonds are the weakest because they are the longest. Double and triple bonds are stronger because they are smaller and held tighter to the atoms.

Daniel_Frees_1L
Posts: 40
Joined: Fri Sep 28, 2018 12:18 am

Re: bond lengths and strengths

Postby Daniel_Frees_1L » Wed Nov 07, 2018 5:21 pm

Another way to look at this that might make more sense is that in a double bond two pairs of electrons are shared between atoms whereas a single bond has only one shared pair of electrons. With more electrons shared, the atoms have to pull closer together and are more 'dependent' on staying bonded with each other to have their outer shells filled.

105085381
Posts: 44
Joined: Fri Sep 28, 2018 12:15 am

Re: bond lengths and strengths

Postby 105085381 » Wed Nov 07, 2018 5:31 pm

Strength of a bond is measured by its' dissociation energy (the energy required to break a bond)

shaunajava2e
Posts: 66
Joined: Fri Sep 28, 2018 12:26 am

Re: bond lengths and strengths

Postby shaunajava2e » Thu Nov 08, 2018 11:37 am

the longer the bong the weaker it is, this is because if the bond length is longer it is easier to break

Letizia Ye 4F
Posts: 62
Joined: Fri Sep 28, 2018 12:28 am

Re: bond lengths and strengths

Postby Letizia Ye 4F » Thu Nov 08, 2018 11:42 am

There are more electrons involved with double and triple bonds, which pulls the atoms closer together and contributes to bond strength.

Peichung Chou 1A
Posts: 30
Joined: Fri Sep 28, 2018 12:21 am

Re: bond lengths and strengths

Postby Peichung Chou 1A » Thu Nov 08, 2018 1:21 pm

Single bonds are the weakest because the valence electrons with which the bonds are made are at the greatest distance, and so there is less attraction between the nucleus and the electrons. As distance increases, the force of attraction between any two objects decreases.

Madelyn Romberg 3L
Posts: 29
Joined: Tue Oct 02, 2018 12:16 am

Re: bond lengths and strengths

Postby Madelyn Romberg 3L » Thu Nov 08, 2018 2:09 pm

In a less scientific way, it is easier to break a thin stick that is about 6 feet long (a single bond) rather than a stick that is 3 centimeters long (a triple bond). Hence, single bonds are weaker than double or triple because they are longer.

Note, the chosen lengths are arbitrary.

Sam Kelly 1K
Posts: 30
Joined: Fri Sep 28, 2018 12:16 am

Re: bond lengths and strengths

Postby Sam Kelly 1K » Thu Nov 08, 2018 2:34 pm

As previous posters have made clear, single bonds are typically longer and weaker, while double and triple bonds are each shorter and stronger. I think the strength of single/double/triple bonds also has to do with the lone electron pairs, however. In a single bond, for example, you will typically have unbonded pairs of electrons in close proximity to one another, making the bond less stable and weaker. Alternatively, in a triple bond, you will likely have a single lone pair on each atom, facing outwards, thus not weakening the strength of the bond. I may be wrong however, but I think this is how it works.

ran2000
Posts: 66
Joined: Fri Sep 28, 2018 12:15 am

Re: bond lengths and strengths

Postby ran2000 » Sat Nov 10, 2018 8:18 pm

Single bonds are the weakest since only one electron pair is being shared. Thus, the force of attraction between the nucleus and the shared pair is low. However, with double bonds, the area of electron density is much more dense/strong since more number of electrons are being shared and thus the force of attraction between the nucleus and the shared pair is stronger. Consequently, the double bond is also shorter. The same can be applied to explain why triple bonds are even stronger than double bonds.


Return to “Bond Lengths & Energies”

Who is online

Users browsing this forum: No registered users and 1 guest