CHEMICAL BONDING by: Jingxi and Slin
History of Van der Waals forces:
Van der Waals was born in Leiden,Netherlands to Jacobus van der Waals and Elisabeth van den Burg. He became a school teacher, and later was allowed to study at the university, in spite of his lack of education in the field of classical languages. He studied from 1862 to 1865, earning degrees in mathematics and physics.
Van der Waals' doctoral thesis was entitled Over de Continuïteit van den Gas- en Vloeistoftoestand (On the continuity of the gas and liquid state). In this thesis he derived the equation of state bearing his name. This work gave a model in which the liquid and the gas phase of a substance merge into each other in a continuous manner. It shows that the two phases are of the same nature. In deriving his equation of state van der Waals assumed not only the existence of molecules (which in physics was disputed at the time), but also that they are of finite size and attract each other. Since he was one of the first to postulate an intermolecular force, however rudimentary, such a force is now sometimes called a van der waal's force.
Interesting Facts about Chemical Bonding:
Pure ionic bonding is not known to exist. All ionic bonds have a degree of covalent bonding or metallic bonding. The larger the difference in electronegativity between two atoms the more ionic the bond. Ionic compounds conduct electricity when molten or in solution. They generally have a high melting point and tend to be soluble in water.
In an ionic bond, the atoms are bound by attraction of opposite ions, whereas, in a covalent bond, atoms are bound by sharing electrons. In covalent bonding, the molecular geometry around each atom is determined by VSEPR rules, whereas, in ionic materials, the geometry follows maximum packing rules. Thus, a compound can be classified as ionic or covalent based on the geometry of the atoms.
Reflection:
From this, we learnt more facts about chemistry. Without Van der Waal, we probably would not be so advanced in chemistry and a lot of medical achievements that we made today would not have been discovered. The facts that we learnt helped us to better understand chemical bonding. And they are things that we cannot find
