19. The element neon (Ne), which is used in signs, differs from both fluorine (F) and sodium (Na) by one proton each. Sodium, an alkali metal, and fluorine, a halogen, are both
extremely reactive. In contrast, neon, which is a noble gas, is highly unreactive. Use the
information contained on a periodic table to explain the difference in their chemical
properties.

intermolecular forces are the forces between molecules or particles.

there are two kinds of van der waals forces: weak london dispersion forces and stronger dipole-dipole forces.

in molecule of water there are dipole-dipole forces between negatively charged oxygen from one molecule of water and positively charger hydrogen of another molecule of water.

hydrogen bond is an electrostatic attraction between two polar groups that occurs when a hydrogen atom (h), covalently bound to a highly electronegative atom such as flourine (f), oxygen (o) and nitrogen (n) atoms.