Electrons are subatomic particles that have an elementary charge of (-1) magnitude. The charge held by an electron is equal in magnitude and has the opposite sign to the charge carried by a proton. Electrons, Protons, and Neutrons are the fundamental particles that are made up of the entire universe.

In this article, we will look into Electron Definition. Discovery of Electrons, Application of Electrons, and others in detail.

What is an Electron?

Electron is a subatomic particle having a negative electric charge. It is one of the three fundamental subatomic particles, along with protons and neutrons, that form atoms. Electrons can be found primarily in two states, which are:

• Bound Electrons: Bound electrons are electrons attracted to the atom’s positively charged nucleus and are found in orbitals around the nucleus. The energy of this electron is quantized, meaning it can only exist in certain specific energy levels.
• Free Electrons: Free electrons are not bound to any particular atom and can move freely throughout a material. These electrons are responsible for the electrical conductivity of metals and semiconductors.

Charge of Electrons

Electron is a negatively charged particle and the charge on the electron is negative 1.602 × 10^-19 coulomb.

Mass of Electrons

Mass of an electron is 9.10938356 × 10^-31 kilograms. Mass of Electron is neligible as compared to the mass of Protons and Neutrons.

What is Electron Made Of?

Electrons belongs to a group of subatomic particles called Leptons, that are fundamental or elementary particles. Therefore, electrons are not composed of other particles and are considered fundamental and indivisible.

Discovery of Electron

Electron was discovered by English physicist J.J. Thomson in 1897 during his experiments with cathode rays.

He observed that the cathode rays were deflected by electric and magnetic fields, leading him to conclude that they were made of particles, which he called “corpuscles” and later termed “electrons.” The term “electron” was coined in 1891 by G. Johnstone Stoney.

Rutherford Electrons Model

Rutherford Model, proposed by physicist Ernest Rutherford in 1911, described an atom as having a tiny, dense, and positively charged core called the nucleus, around which the light, negative electrons, revolve at some distance, much like planets revolving around the Sun. This model was based on Rutherford’s famous gold foil experiment, in which he observed that most alpha particles passed straight through the gold foil, suggesting that atoms are mostly composed of open space, while a few were deflected, indicating interactions with other positively charged particles within the atom.

Bohr Electrons Model

Bohr Model, proposed by Niels Bohr in 1913, is a structural model of the atom that improved upon previous models using the principles of quantum theory. According to the Bohr model, electrons move around the nucleus of an atom in distinct circular orbits or shells, similar to how planets orbit around the Sun. The model is also known as the planetary model of the atom.

It introduced the concept that electrons can only exist in discrete shells with specific energy levels and cannot exist between these orbits. The Bohr model applies to hydrogen-like species containing one electron only, such as the hydrogen atom and singly ionized helium.

Fundamental Properties of Electrons

Electrons have three fundamental properties that includes,

• Charge
• Mass
• Spin

Now let’s learn the same in detail.

Charge

The most well-known property of an electron is its negative electric charge. The charge of an electron is denoted by ‘e‘ and is approximately equal to -1.602 × 10^-19 coulombs (C). This charge is the same for all electrons and is fundamental to chemical and physical properties of matter.

Mass

Mass of an electron is minimal, approximately 9.109 × 10-31 kilograms (kg). It is about 1/1836 the mass of a proton. The small mass of electrons means that they contribute very little to the overall mass of an atom.

Spin

Electrons have an intrinsic angular momentum, or spin, of 1/2 ħ. This means they can have two possible spin states, up or down. Spin is an essential property of electrons that plays a role in many physical phenomena, such as magnetism.

Formulas Related to Electrons

Electron are used to explain various concepts in an atom and some of the formulas related to electrons are,

Energy of Electron in n^th Energy Level

Energy of an electron in the nth level of a hydrogen atom can be calculated using the formula:

E(n) = -1/n² × 13.6 eV

Where, n is the Principal Quantum Number that represents the energy level of the electron.

Wavelength of Electron

The wavelength of an electron can be calculated using the de Broglie Wavelength formula:

λ = h/p

where,

• λ is the Wavelength
• h is Planck’s Constant
• p is the Momentum of Electron

Electron Orbits and Energy Level

The energy level of an electron is determined by the orbital in which it is present. Orbitals with lower energy levels are closer to the nucleus, and orbitals with higher energy levels are farther from the nucleus. Electrons can move between orbitals by absorbing or emitting energy. An electron cannot exist in between energy levels of the orbitals.

Quantum Mechanics and Electrons

One of the fundamental principles of quantum mechanics is that the electron exhibits wave-particle duality, meaning it can behave as both like particle and like wave. According to the Heisenberg Uncertainty Principle, it is impossible to know an electron’s position and momentum simultaneously.

Quantum mechanical model of the atom, proposed by Erwin Schrödinger, treats electrons as matter waves and uses wave functions to describe the probability of finding an electron in a given region within the atom. This model has successfully explained the behavior of electrons in atoms and molecules, and it forms the basis of our understanding of chemical bonding and the flow of electrons in materials and devices.

Role of Electron in an Atom

• Electrons are negatively charged particles that balance the protons’ positive charge in the atomic nucleus, thereby making the atom electrically neutral.
• Electrons are also responsible for atoms’ shape, orientation, and bonding.

Electricity and Conductivity

Electrons play a crucial role in the flow of electricity in materials and devices. A material’s electrical conductivity depends on the number of free electrons it has available to carry the electric charge. Materials that have free electrons are good conductor of electricity such as metals, etc.

The valence electrons of the atoms are loosely bound to the atomic nucleus in case of metals, allowing them to move freely through the material. It makes metals good conductors of electricity. In contrast, materials with few free electrons, such as nonmetals, are poor conductors of electricity.

Application of Electrons

Some applications of electrons are,

• Electronics: Electronics is a broad field, including the design, development, and application of electronic devices and systems. Electrons are the primary charge carriers in these devices, enabling the flow of electricity and the operation of various components like transistors, diodes, and integrated circuits.
• Semiconductor Devices: These devices rely on the controlled movement of electrons to amplify, switch, or rectify electronic signals.
• Electrochemistry: Electrons are involved in many electrochemical processes, including electrolysis, corrosion, and battery operation.
• Vacuum Tubes: Vacuum tubes were the earliest electronic devices before the development of semiconductors. They utilize the flow of electrons in a vacuum to amplify or generate electronic signals.
• Electron Microscopes: Electron microscopes utilize electrons to magnify objects, providing an extremely high level of resolution compared to optical microscopes. It allows the scientists to study the detailed structure of materials at the atomic and molecular levels.

Read More,

• Atoms
• Atomic Structure
• Composition of an Atom

FAQs on Electrons

1. What is Electron and Protons?

• Electron is the fundamental particle with negative charge
• Proton is the fundamental particle with positive charge

2. Why is it Called an Electron?

Electron gets its name from two words electric and ion.

3. What is Charge of Electron?

The charge of an electron is negative and its magnitude is 1.602 × 10^-19 coulomb.

4. Who Discovered Electrons?

J.J. Thomson discovered the electron in 1897.

5. What is the Symbol to Represent Electron?

The symbol for an electron is “e⁻.”

6. What is Relative Mass of Electron?

The relative mass of an electron is extremely small, about 1/1836 of a proton.