Solid Xenon:
Solid xenon is expected to exhibit Van der Waals (or London dispersion) forces. These forces arise due to temporary dipoles that form when the electron distribution within xenon atoms becomes uneven. Given that xenon is a noble gas, it exists as a monatomic gas in its natural state but can solidify under low temperatures and high pressures. Its weak intermolecular forces result in a low melting point compared to ionic or covalent compounds.
Calcium Fluoride:
Calcium fluoride has ionic bonding. This occurs because calcium (Ca), a metal, readily donates its two valence electrons to fluorine (F), a non-metal, which has high electronegativity and accepts those electrons to complete its outer shell. The resulting calcium ions (Ca2+) and fluoride ions (F–) attract each other strongly, creating a stable ionic lattice structure characteristic of ionic compounds.
Rubber:
The bonding in rubber is primarily covalent while also exhibiting some cross-linking features. Rubber is made up of long polymer chains that are linked together through covalent bonds. The flexibility of rubber comes from the ability of these polymer chains to move past one another easily, yet the covalent bonds provide the necessary structural integrity. The cross-linking enhances its elasticity and durability, allowing rubber to stretch and return to its original shape.
Tungsten:
Tungsten exhibits metallic bonding. In tungsten, atoms release some of their electrons to form a ‘sea of electrons’ that are free to move throughout the metal structure. This metallic bonding is responsible for tungsten’s excellent electrical conductivity, malleability, and toughness. The strong attraction between the positively charged tungsten ions and the delocalized electrons contributes to tungsten’s high melting point and robustness.