Who discovered the Electron?

What is an Electron? – The electron is an atomic particle where its electric charge is negative. They are the carriers of electricity in solids and are made up of atoms.  They are the first in the lepton particle family and because they have no components of their own they are also treated as elementary.

The discovery of Electron: Electron was first discovered by Joseph John Thomson (J.J. Thomson).He was a Cavendish professor of Physics at Cambridge University and also the director of the Cavendish laboratory until 1919.

History: 

For the history we will start with how the electric forces effect came into light. AS early as possible the Greeks used to notice that amber attracted small objects when you rub it with fur. Along with lightning they also discovered electricity in its rawest form. English scientist William Gilbert coined the term electrica which basically means that substances with similar properties to that of amber when they attract small objects after being rubbed with fur. Both the words Electricity and electric comes from the Latin word ēlectrum which again came from the greek word for amber. Discovery of two kinds of charges was done in the early 1700. It was discovered by French chemist Charles Francois du Fray when he experimented with a gold leaf which was charged and it seemed to be repulsed by glass when rubbed with silk. The same gold leaf was attracted by an amber rubbed with wool. So this experiment denoted that electricity has two kinds of fluids which is vitreous fluid and resinous fluid. Both the fluids can neutralise one another. Here it is noteworthy that Benjamin Franklin proposed that electricity was actually not from different kinds of fluids but same type. He then named them positively and negatively charged respectively.

1881- Stoney coined the term electrolion.

1891- This was changed to electron as it apply describes the elementary charges.

1906 – It was proposed to be changed to electrion but the changes did not happen.

It was later decided to keep it Electron since the word denotes electric and ion and ion is used to denote proton and neutron.

1838-1851 – During this time British philosopher Richard Laming developed that atom is made up of matter which is surrounded by subatomic particles that have charges. Then it was developed that electricity has both negative and positive charged fluids and the interaction was governed by the inverse law. However it was later that Stoney who said that the positively and negatively charges were attached to atoms.

Characteristics of an Electron:

1. The first characteristic of an electron is that it is negatively charged. They are elementary particles because they do nor have substructure.
2. The electron has a mass which is about 1/836 that of the proton. The electron has an angular momentum and is being expressed in plank constant. No two electrons can occupy the same quantum state.
3. Electrons exhibit properties both of waves and particles. They will collide with each other and also detract from light. Electrons have lower mass and hence they have longer wavelengths for a given energy.
4. Electrons play an important role in some physical phenomenon Eg- magnetism, Electricity, Chemistry, thermal conductivity, etc and also they take active participation in gravitational, electromagnetic interactions. Since they have charge it also has an electric field.
5. Electrons radiate or absorb energy in the form of photons. Special kind of telescopes can detect electron plasma in the outer space. We can use electrons in many fields like welding, cathode ray tubes, solar panels, lasers, particle accelerators, electrolysis, etc.
6. When we talk of electrons and their interactions we can see that they are of importance in the field of Chemistry and nuclear physics. The Coulomb force between the positive protons with atomic nuclei and negative electrons act in them and create the atom.
7. Electrons can participate in some nuclear reactions and in that case they are known as beta particles. They can be created by beta decay or isotopes and in high energy collisions such as atmospheric cosmic ray interference.
8. Electron has an antiparticle known as positron and it has electric charge of opposite sign to that of electron. When an electron collide with positron then they produce gamma ray photon.

Electron fundamental properties:

1. The mass for an electron is approximately 9.109X10-31 kgs. This corresponds to a rest energy of 0.511MeV.
2. They have electric charge of -1.602176634 X 10 -19 Coulombs, Which is basically the standard unit of charge for subatomic particles. This called as the elementary charge.
3. They are negatively charged and has an intrinsic magnetic moment along the axis where it spins.
4. Electrons have no substructure. However, in some cases they will disintegrate into spinon, orbiting and holon.
5. The electron will generate an electric field that always exerts a force for a particle with a positive charge. The strength of this force is determined by Coulombs inverse square law. When the electron is in motion it will generate a magnetic field.

Refer: Structure Of Atom from Class 11 Chemistry – Find All the Questions & Answers