Molecular attraction

Molecular attraction occurs when neutrally-charged molecules nevertheless experience the uneven distribution of electrons over their structure due to London Forces induced by random variations of electron density occurring in non-polar compounds, hydrogen bonding due to the production of what is essentially a bare proton when it is bonded with a strongly electronegative element such as fluorine, oxygen or nitrogen, and the dipole-dipole interaction between compounds that are polar, such as salt. The properties of liquids and the expansion of water ice when it freezes are due to molecular attraction.

Additional recommended knowledge

What is the Sensitivity of my Balance?

What is the Correct Way to Check Repeatability in Balances?

Daily Visual Balance Check

Source

Dr. Walt Volland, Intermolecular Forces