What is free electron theory and how it explains the properties of metals?
Assumptions of Classical free-electron theory: All metals contain large number of free electrons which move freely through the positive ionic core of the metals. Since these free electrons causes conduction in metal under the application of electrical field, they are called as conduction electrons.
What is free electron model theory?
A free electron model is the simplest way to represent the electronic structure of metals. According to this model, the valence electrons of the constituent atoms of the crystal become conduction electrons and travel freely throughout the crystal.
How does free electron theory explain the metallic bond?
Metallic bonding may be described as the sharing of free electrons among a lattice of positively charged metal ions. That is to say, instead of orbiting their respective metal atoms, they form a “sea” of electrons that surrounds the positively charged atomic nuclei of the interacting metal ions.
What is free electron theory of metallic bond?
The valence electrons of metallic atoms are free to move in the spaces between ions from one place to another place within the metallic specimen similar to gaseous molecules so that these electrons are called free electron gas.
What do you mean by free electron?
1 : an electron within a conducting substance (as a metal) but not permanently attached to any atom. 2 : an electron moving in a vacuum.
What is the significance of free electron theory?
1) It verifies ohm’s law. 2) It explains electrical and thermal conductivities of metals. 3) It derives Widemann-Franz law. 4) It explains optical properties of metals.
What do electrons do in a metallic bond?
In contrast to electrons that participate in both ionic and covalent bonds, electrons that participate in metallic bonds delocalize, forming a sea of electrons around the positive nuclei of metals. The availability of “free” electrons contributes to metals being excellent conductors.
What is metallic bonding easy explanation?
A metallic bond is a type of chemical bond formed between positively charged atoms in which the free electrons are shared among a lattice of cations. In contrast, covalent and ionic bonds form between two discrete atoms. Metallic bonding is the main type of chemical bond that forms between metal atoms.
What is free electron Class 10?
The electrons in the outer shells (valence electrons) are loosely bound to. the atoms, hence they are free to move easily within the metal surface but cannot leave the metal surface. Such electrons are called free electrons.
What is free electron Class 12?
The energy and angular momentum of an electron in an orbit is always constant. These electrons are called free electrons, what we mean by free electrons are electrons that can move around in the crystal lattice which forms the element or any substance.
What is the significance of Fermi energy?
It is important in determining the electrical and thermal properties of solids. The value of the Fermi level at absolute zero (−273.15 °C) is called the Fermi energy and is a constant for each solid. The Fermi level changes as the solid is warmed and as electrons are added to or withdrawn from the solid.
What are the success of quantum free electron theory?
Merits of quantum free electron theory 1. It successfully explains the electrical and thermal conductivity of metals. 2. It can explain the Thermionic phenomenon.
When was the free electron theory of Metals proposed?
The treatment of a metal as containing a gas of electrons completely free to move within it. The theory was originally proposed in 1900 to describe and correlate the electrical and thermal properties of metals.
How are electrons responsible for the conductivity of metal?
According to this theory, metal contains free electrons which are responsible for the electrical conductivity and electrons obey the laws of classical mechanics. 2. Quantum Free Electron Theory: In 1928 Sommerfeld developed the quantum free electron theory.
What are the merits of classical free electron theory?
What are the merits and demerits of classical free electron theory? 1 It verifies ohm’s law. 2 It explains electrical and thermal conductivities of metals. 3 It derives Widemann-Franz law. 4 It explains optical properties of metals.
What are the properties of a free electron?
Free Electron means unbound electron of the atom of any metal which can move freely. Many properties of metal-like electrical conductivity, magnetic susceptibility, Thermal conductivity, Mechanical strength, optoelectronic properties, etc. depend on the free electrons.