easechemistry

All F2, Cl2, Br2 and I2 belong to same halogen group, are non polar homo- diatomic molecules. Such molecules don't have permanent poles to generate dipole-dipole interaction. Existence of non polar molecules in liquid and solid state shows that they also have ability to create intermolecular forces and these intermolecular forces are London dispersion forces. Recall here Physical states ( solid, liquid and gas) are directly related to strength of intermolecular forces. Stronger the intermolecular forces , substance will be liquid or solid. Order of intermolecular forces in different physical states is Solids> liquid>gas  London forces are weaker than dipole-dipole forces.To generate London forces, non polar molecules have to be polarized, the size of atoms decide the strength of London forces.  Larger the molecules more will be the polarizibility - it is quantitative measurement of the extent to which the electronic cloud of non polar molecules can be polarized or disto...

 Recall that it is the molecular weight and extent of intermolecular forces which determine physical states( solid, liquid and gas) of substances.  Order of Intermolecular forces strength in substances is : Solids>liquid>gases When we look at molecular weight , it seems water would be in gaseous state and hydrogen sulfide be in liquid state. But here in case of water , water has hydrogen bonding . Hydrogen bonding is limited to  three highly electronegative atoms ( F, O and N). In water H2O, Hydrogen is attached to 2nd highest electronegative atom i.e O of periodic table.Hence water is having relatively strong intermolecular forces in form of hydrogen bonding. On other hand Hydrogen sulphide is having simple dipole-dipole interaction. Order of intermolecular forces in strength is  Hydrogen Bonding> dipole-dipole forces> London forces  Hydrogen bonding among water H2O molecules On other hand Hydrogen sulphide is having simple dipole-dipole interactio...