[NewtoAtoms]

Hello Chemists,

I have a questions I am hoping someone can answer for me.

Which of the following two has the smaller dipole-dipole force:

F2, or Kr

VERY ODD QUESTION I KNOW... but here is my rational and perhaps if I am off could someone offer some assistance.

F2 is a non polar molecule therefore it is has no dipole forces
Kr is an unreactive noble gas, which also doesn't have dipole forces, however it's just a lone element.

Therefore I would conclude that F2 has a smaller dipole-dipole force

Am I correct?

Thank you everyone!!!

[nj_bartel]

 http://wiki.answers.com/Q/How_can_you_tell_if_there_is_a_dipole_moment_or_not

neither have any dipole moment.  I believe you're thinking of London dispersion forces, which are primarily based upon MW.

[NewtoAtoms]

Thank you for your response,

However my question asks:

Which of the substances F2, Kr, CH4, HF

has the smallest dipole-dipole forces

and I don't know if it would be either F2 or Kr.

Thank you for your help.

[nj_bartel]

well, ch4 doesnt have a dipole moment either, only LDF's.  CH4/Kr are both radially symmetric, while F2 isn't, but Kr has by far the largest MW of those given.  My guess would be Kr, but I'm not entirely sure.