In the world of chemistry, metals are the class of elements that are known for their unique chemical and physical properties. In fact, metals form an integral part of industrial chemistry and it's impossible to imagine a world without metals. To understand the internal structure of metals, we need to know 'what is metallic bonding'? Metallic bonding, as the name suggests is a bonding between atoms within the metals.
In its very essence, metallic bonding involves the sharing of electrons among lattice of metal atoms. In a metal, the electromagnetic interaction between delocalized electrons called as conduction electrons and the metal nuclei is called as metallic bonding. Basically, the most important metallic bonding theory that easily explains the internal bonding mechanism of metals uses the s, p, d, f and other orbitals theory. It is more popularly known as molecular orbital theory and provides a more comprehensive understanding of the metallic bonding concept.
Almost all metals are examples of metallic bonding and their physical properties can easily be explained using the molecular orbital theory. For the uninitiated, molecular orbital theory is a concept taught in higher chemistry courses and deals with molecules in the same way as atoms. Since it's easily interpreted by using orbital diagrams, molecular orbital theory comes handy in providing explanations about various concepts of chemistry. It is noteworthy that owing to metallic bonding metals possess various properties. Let us discuss more about them.
Metallic Bonding Properties
Owing to the internal metallic bonding, metals posses various properties. Here are some of the metallic bonding properties possessed by metals. Solid metals have various properties like they can conduct heat and electricity, have high melting point and boiling point and are strong solids. Malleability (ability to be flattened without breaking), ductility (ability to be drawn into wires), metallic luster and opaqueness are some of the other features of metals.
Another feature of metals is conductivity. Solid and liquid metals conduct heat and electricity owing to the presence of free electrons in them that acts as charge carriers. That is why electrical conductivity of metals plays a crucial role in determining which metals are best suited for use as electrical conductors. Similarly, owing to strong or weak metallic bonding, metals have higher and lower boiling and melting points. In general, higher the number of delocalized electrons and more closely the atoms are packed in a metal, higher will be the melting and boiling point. Similarly owing to the presence of delocalized electrons metals are able to roll on over each other when pressed and this imparts them properties like malleability and ductility.
Metallic Bonding Examples
Like NaCl is an example for ionic bonding, various metals like iron (Fe), lithium (Li), potassium (K), gold (Au), silver (Ag) are all examples of metallic bonding. Even the alloys of metals are examples of metallic bonding. Brass, an alloy of copper and zinc, Terfenol-D (a magnetostrictive alloy) and various chemical elements are some other metallic bonding examples. Most of the metals have only one or two valence electrons and their ionization energies are very low, that is, the valence electrons are not very tightly bound to the atom and they are easily mobile from one to the other atom. This ease with which mobile electrons move in a crystal lattice determines the bond, that means, ionic, covalent or metallic bonding. The properties exhibited by metals are due to metallic bonding as mentioned in the above paragraphs. For instance, consider gallium, molten gallium is a very non volatile liquid in its molten form and it is due to the strong metallic bonding in gallium.
Metallic bonding forms one of the various forms of chemical bonds studied in chemistry. This was some brief information about metallic bonding that is the main reason for various physical properties of metals.