Sharing detached electrons among positive ions with the help of electrons to give the substance a particular shape is called a metallic bond. Since metals have a low ionization energy the valence electrons can be delocalized. These delocalized electrons are free to move and form electron sea. Let us discuss the working and properties of metallic bond.
- Overlapping of the s and p orbitals which are the outer energy levels of metal atoms.
- None of the valence electrons that take part in the metallic bond are shared with the neighbour atom, nor lost to form an ion.
- The electrons form a electron sea which helps valence electrons to move from one atom to another atom. This is an oversimplification of metallic bonding process.
- Calculations based on density functions or electronic band structure are quite accurate.
- Metallic bonding may result due to more delocalized energy state than delocalized electrons of the material leading to make the localized unpaired electrons mobile and delocalized.
- The energy state of electrons can be changed as well as their movement throughout a lattice in all directions are allowed.
- Bonding can also occur in metallic cluster formation where delocalized electrons move around localized cores.
- Formation of bonds depends on conditions. For example, consider the metal hydrogen under high pressure but as pressure decreases, bond is changed to nonpolar covalent from metallic.
- Thermal conductivity – The free electrons transfer the energy away from the heat source and vibrations of atoms travel as a wave.
- Malleability – Metals are capable of being molded into a shape as the bonds between the atoms can readily break and reform. The binding force between metals is nondirectional therefore, the electrons in crystals may be replaceable.
- Electrical conductivity – Because the electrons in the electron sea can carry charge and are free to move the metals are brilliant electrical conductors.
- Ductility – Metals can be drawn into thin wires as the local bonds between atoms can be easily broken and reformed. Also, thin sheets can be formed.
- Metallic lustre – Metals are shiny and display metallic lustre. Once a certain minimum thickness is achieved they become opaque. The attraction between atoms is strong therefore, this makes the metals strong and gives them a high melting point, low volatility, high density, and high boiling point. There are a few exceptions like mercury, etc.
To learn various other chemistry concepts such as Redox reaction, Oxidation, Oxidising agent and more in an interesting way, subscribe to BYJU’S YouTube channel