S.2.4.1 - Bonding continuum

Elements are always fully ionic, covalent, or metallic.

• Look at Aluminum Chloride ( $AlCl_3$) exhibiting properties of both Covalent & ionic bond.

• Metalloids exhibit both covalent and metallic Properties.

• $\therefore$ bonding is best described as a continuum between these types

Triangle

• Anton Eduard van Arkel & Jan Ketellar constructed a triangular diagram to represent the continuum

• Note the Vertices mean a pure type

• Sides of the triangle represent intermediates between two bonding types

  • This means $AlCl_3$would be placed half-way between Strongly Ionic & Covalent

    

    Properties of materials based on bonding type

  • Solubility and Volatility Solubility and Volatility ( How easily a substance will vaporize ) is described by bond-type, structure, and if applicable intermolecular forces. Electrical Conductivity depends on the presence of mobile charged particles . More is described below.

  

Other notable properties

• Brittleness

  • Opposite of malleability ( capacity to be resized and extended w/out breaking )

  • Ionic crystals break easily

  • Metals are highly malleable

  • Break bc cannot deform easily ( rigid )

    • The atoms or ions cannot slide past each other

• Elastic

  • Able to change shape when subject to force and return to original shape when removed

  • Metal springs

    • Elastic due to the metallic bonding

  • Rubber

    • Due to the long polymer chains uncoiling and coiling

  • Opposite is plasticity

    • Modeling Clay

• Corrosive

  • Generally refers to how a chemical species reacts to its surrounding environment ( Chemical reactions )

  • Often used to describe oxidation of metals in the presence of water & oxygen

It is important to note though materials don't behave in a manner typical of their bonding type. Despite being both metals Mecury is votatile & aluminum has low density. In these cases more than 1 bonding type can contribute to property of substance.