Describe the trend in boiling point of the halogens.

The boiling point of the halogens increases as you go down the group. The halogens exist as diatomic molecules, with both atoms sharing an electron to completely fill the outer shell. The increase in boiling (and melting point) can be attributed to the increase in intermolecular forces (van der Waals). The number of electrons increases in each element going down the group, this leads to an increase in temporary dipoles which can be set up. (side note, van der Waals forces: electrons move randomly around the nucleus of an atom, at any one time there may be more electrons on one side of a molecule creating a temporary negative charge on that side and a positive charge on the other - an instantaneous dipole. This is what holds the halogens together) In addition, the size of the molecules increases going down the group - this gives more 'space' for the electrons to sit in, this results in a reduced repulsion i.e. the electrons repel each other less. However, this is a side factor and is only particularly relevant for fluorine. This means that it is required to supply more heat in order to overcome these forces.

LW
Answered by Lucy W. Chemistry tutor

43069 Views

See similar Chemistry GCSE tutors

Related Chemistry GCSE answers

All answers ▸

What is distillation?


c) What does the rate of reaction depend on? (2 marks)


Chlorine is in group 7. What is the charge on its ions, and is the charge positive or negative?


85 cm^3 of 0.05 mol/dm^3 sulfuric acid is used to neutralise 15 cm^3 of sodium hydroxide of an unknown concentration. Given that the chemical formula of the reaction is 2NaOH + H2SO4 => NA2SO4 + 2H2O, find the concentration of the sodium hydroxide.


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning