From ancient civilizations to the contemporary age, metals have been prized for their beauty and
rarity . However, they are also valued for their unique properties. Ever wondered why metals are so shiny, strong, malleable, and good conductors of heat and electricity?
all due to their atomic structure and bonding. Metals have a crystalline structure where atoms are arranged in a regular pattern. This structure allows electrons to move freely throughout the metal, collective sharing of a 'sea' of valence electrons among positively charged metal ions.
Which is why metals are such good conductors of electricity and heat. The free electrons also reflect light, giving metals their characteristic shine.
The strength and malleability of metals come from the metallic bonds that hold the atoms together. These bonds are strong yet flexible, allowing metals to be hammered into thin sheets or drawn into wires without breaking
Let's discuss the following four properties of Metal one by one and understand the science behind them
1) Malleability
2) Electrical Conductivity
3) Thermal conductivity
4) Metallic Luster
What is Malleability?
Malleability is a property of metals that allows them to shaped into different shapes without fracturing.
Let's understand with an example: When an ionic crystal is beaten with a hammer, it shatters into many smaller pieces. This is because the atoms in the crystals are held together in a rigid lattice that is not easily deformed. The force from the hammer causes the crystal structure to fracture, resulting in the shattering of the crystal.
However, metals such as gold, silver, iron, copper, etc., expand when hammered, because the metal lattice is deformed but not fractured. But why?
Let's see what makes metals so malleable.
In the case of metals, the sea of valence electrons in the metallic bond enables the deformation of the lattice. Atoms in most metals can move away from their nearest neighbors by sliding and make bonds with other atoms. This is known as dislocation motion, and it is related to how metals can be extensively deformed without producing cracks and voids.
Thanks to malleability, we can make a wide range of engineering products. Processes like forging, rolling, deep drawing, and extruding all rely on the malleable nature of metals
Electrical Conductivity
Electrical conductivity is a measure of the ability of a substance to allow a charge to move through it. In Matel due to metallic bond the movement of electrons is not restricted in the electron sea so when a potential difference is applied, delocalized electrons, which are not bound to a specific atom, move toward the positive charge. This property makes metals generally excellent conductors of electricity, allowing them to efficiently transmit current when connected to an electrical potential, like a battery.
Thermal Conductivity of Metals: When one end of a metallic substance is heated, the kinetic energy of the free electrons in that region increases. These energized electrons collide with neighboring electrons, transferring their excess energy. The higher the mobility of these electrons, the faster the heat is conducted. Metallic bonding, characterized by a "sea" of delocalized electrons, facilitates efficient heat transfer. These mobile electrons can rapidly transport thermal energy throughout the metal, making metals excellent conductors of heat.
Metallic Luster
When light is incident on a metallic surface, the energy of the photon is absorbed by the sea of electrons () that constitute the metallic bond. The absorption of energy excites the electrons, increasing their energy levels. These excited electrons quickly return to their ground states, emitting light in the process. This emission of light due to the de-excitation of electrons attributes a shiny metallic luster to the metal.
The electron configuration of metals allows them to be polished to a high degree, further enhancing this lustrous property