Electron Theory

Introduction

One of the foundations to understanding materials is understanding how electrons behave in solids. The optical, magnetic, thermal, and electrical properties of materials can all be explained by the electron theory of solids. In other words, the electron theory offers crucial foundational knowledge for a technology that is sometimes regarded as the cornerstone of contemporary society. I'll show you some examples to do this. Electric generators, motors, loudspeakers, transformers, tape recorders, and cassettes all utilize magnetic materials. Lasers, optical communication, windows, lenses, optical coatings, solar collectors, and reflectors all make use of a material's optical qualities. Devices for cooling and heating as well as heat shields for spacecraft use thermal properties.

Silver and copper are two materials that conduct electricity quite well. Porcelain and quartz are good insulators. At room temperature, semiconductors are typically poor conductors. The electrical conductivity does, however, increase with the addition of traces of specific elements.

The electronics sector has expanded to yearly revenues of about $8 trillion since the transistor was developed in the late 1940s. The electronics industry has relied on materials and materials research since its inception.

Bohr’s Model of an Atom

Atoms or collections of atoms (molecules) that are chemically or physically bound together make up all matter. We must take into consideration a basic model of the atom in order to comprehend something about the nature of electrical charge. In this concept, also referred to as the Bohr model, the positively charged nucleus of an atom is orbited by negatively charged electrons, which are known as shells or orbits. These circular orbits are referred to as orbital shells because each orbit or shell has a defined energy.

Protons, which are positively charged, and neutrons, which are electrically neutral and have no charge, are both present in the nucleus. Electrons with a negative charge that is equivalent to the proton's charge in size orbit the nucleus. The protons and neutrons in the nucleus are around two thousand times heavier than these electrons.

Bohr's Atomic Model Postulates

In an atom, negatively charged electrons move in defined circular orbits or shells that circle the positively charged nucleus.

These circular orbits are referred to as orbital shells because each orbit or shell has a defined energy.

The energy levels are denoted by the integer quantum number (n=1, 2, 3, etc.). In this quantum number range, n=1, the nucleus side has the lowest energy level. An electron is said to be in the ground state when it has the lowest possible energy level. The K, L, M, and N... shells are given to the orbits with n=1, 2, 3, and 4.

Since there are an equal number of protons and electrons in a stable atom, the atom is generally neutral and has no charge. However, electrons can go from one substance to another if we rub two specific materials together. As a result, the atom acquires a net positive or negative charge, changing its stability.

When an atom within a substance loses electrons, it becomes positively charged and is referred to as a positive ion. Conversely, when an atom receives an electron, it has an excess negative charge and is known as a negative ion. Electrostatic consequences may result from these charge discrepancies. A difference in charge between your hair and the rest of your body, such as that caused by combing your hair with a nylon comb, could cause your hair to stand on end when your hand or another differentially charged body is brought close to it.

Based on the placement of the element in the periodic table, it is possible to forecast the number of electrons that will occupy a particular orbit within an atom. Depending on their energy level, the electrons in every atom occupy a certain orbit or shell. From the nucleus outward, electrons occupy each of these shells within the atom. These three shells can each hold up to two electrons in the first, innermost shell, eight in the second, and 18 in the third.

All electrons and protons have an electrical charge, but because it is so insignificant, we need a more practical unit of charge, which we call the coulomb. The total charge carried by 6.21 x 10^¹⁸ electrons is measured in coulombs (C).

Thus, the charge of a single electron is only 1.61 x 10^-¹⁹ Coulomb

A conductor is a substance that possesses a large number of free electrons that can serve as charge carriers and let current to flow freely. Aluminum, copper, gold, and iron are a few examples of good conductors. To repel the nucleus, a negligible amount of external energy is needed. These energies can come from electrostatic fields, heat, or light. A free electron is an atom that has been freed from its atom and can move freely within the material's crystal structure. These unbound electrons are what turn into a material's charge carriers. Large amounts of free electrons in a material make it a good conductor of heat and electricity.

When free electrons are present in a material, their direction of travel is random; however, if an external force is applied, the free electrons move uniformly.

Due to their abundance of free electrons that can serve as charge carriers, metals make for the greatest conductors. Insulators are substances that do not conduct charge; these substances' electrons are firmly linked to their atoms' nuclei. Materials made of plastic, glass, rubber, and ceramics are examples of insulators.

The presence of one or more of the following effects—light, heat, magnetism, chemical, pressure, friction—can be used to identify the effects of an electric current flow. For instance, when an electric current is run via a resistive heating element, heat is generated. When an electric current pass through the fine filament wire in the evacuated bulb of an electric lamp, light is created.

Conclusion:

An electron is a negatively charged subatomic particle that can exist either free or bonded to an atom (not bound). An atom has three primary types of particles: protons, neutrons, and the electron, which is bound to it. Together, protons, neutrons, and electrons make up the atom's nucleus.