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Discovery of Electron, Proton and Neutron for IIT JEE

Last updated date: 16th May 2024
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An Introduction

There were many hypotheses before John Dalton’s exceptional theory, and all these hypotheses concentrated on what mass was made of. The scientists eventually understood the subatomic particles forming different types of atoms. It was the first time a theory properly explained and supported the law of conservation of mass, the law of multiple proportions, and the law of constant composition. It is then that three subatomic particles were discovered by the scientists. The discovery of electron proton and neutron propelled various other important discoveries.

Matter is made of atoms. An atom is made of many subatomic particles. In this section, we will learn who discovered electron protons and neutrons and how. Every set of experiments led to the discovery of each subatomic particle. These path-breaking discoveries in the 19th and 20th centuries led to the foundation of Nuclear Physics and its various branches.

It is necessary to learn how the scientists performed these experiments to understand the physical properties of these subatomic particles. You will be fascinated to find out how electron proton neutrons are discovered by distinguishing their features.

How the Electron was Discovered?

Electrons are the subatomic particle that remains outside the nucleus. It is bound by the electromagnetic force of attraction. Despite the huge distance between an electron and a nucleus, the strong force keeps it in its orbit. Sir William Crookes was the one who discovered electrons in the year 1885.

He conducted many experiments by heating metallic electrodes in a vacuum. He was conducting experiments to check the behavioral features of metals when heated in a vacuum. The glass tube in which he was heating the electrodes was partially evacuated. When a source of high-voltage was connected to the electrodes, a stream of highly-energized particles was observed emerging from the negative electrode or cathode to the positive electrode of the anode. Crooks also saw that these particles traveled in a straight line when there is no influence of an external electric or magnetic field. A set of features of these particles was then concluded by the further experiments done by the other scientists. Sir J. J. Thompson, who invented electrons, was an eminent physicist who added to the physical features of electrons.

Crooks, who discovered electrons, and other scientists concluded that these are very small particles that possess very tiny mass and kinetic energy, travel very fast in a straight line, and are negatively charged. They also measured the charge to mass ratio (e/m) and found that they are always the same.

How Protons were Discovered?

Eugen Goldstein, the one who discovered protons,  was experimenting with a perforated cathode (negative electrode). The electrodes were fit into a glass tube containing air, but the pressure is extremely low. He experimented in 1886. During this time, the electron was not discovered and identified. He passed high voltage across the electrodes. He observed a red glow behind the cathode in that tube. This ray was formed in the opposite direction of the electrons flowing forming cathode rays. Hence, the proton was discovered by Goldstein accidentally.

The same experiment was then conducted on anodes resulting in the flow of another ray. This time, the particles had a significant mass but traveled straight when there was no electrical or magnetic field around. The formation of these subatomic particles in the ray has been properly explained. If you read it carefully, you will find who discovered protons and how the features of this subatomic particle have been concluded.

These particles are much heavier than electrons. The charge to mass ratio (e/m) was always the same even if different metals were used to conduct the same experiment. On proceeding further, Rutherford was capable of proving that the hydrogen ion (H+), the resultant of a hydrogen atom losing an electron, had the same properties as that of the positive particles flowing forming rays in 1919.

Discovery of Neutron

James Chadwick, after the end of World War I, returned to England to his mentor Ernest Rutherford. He completed his Ph.D. under Rutherford’s supervision and concentrated his experiments on radioactive decay. Even though Rutherford found protons in an atom, Chadwick found that it was not the only subatomic particle residing inside the nucleus of an atom.

He then conducted his experiments on atomic disintegrations and found that the atomic number of Helium is 2 but its mass number is 4. After carrying on many other experiments, he concluded that only protons can hold two electrons in a Helium atom. Hence, the other subatomic particles, that have the same mass as a proton, did not carry a charge. These particles were neutral but had mass. In 1935, he discovered the presence of neutrons and received the Nobel Prize.

Why Should You Study the Discovery of Electron Neutron Protons?

Every discovery in the world of nuclear physics is no less than a fairy tale. The discovery of something so small is quite fascinating. By learning who invented the proton electron neutron, you will be able to figure out the features of these subatomic particles responsible for the discovery. The way all the scientists distinguished and concluded these particles should be learned by the students.

The discovery of electron proton and neutron is a dimension-altering incident in the world of science. From this level, we have gone so far and these scientists are responsible for such development.

How to Handle IIT JEE Examinations

Apart from studying and memorizing the list of chemicals and chemical equations, there are a few more strategies for dealing with chemistry-related questions and the IIT JEE  test in general.

  • Begin to recall the schematics of chemistry-related questions that featured in past years' papers. These will help you learn and remember the fundamental principles without having to read a lot of text.

  • Make sure you get enough rest while preparing in addition to reading the top JEE books. Maintain a healthy diet and sleep schedule to improve your performance.

  • Year after year, the exam's competitiveness grows, and it grows quickly! One must have the ideal plan in order to crack and qualify for a medical seat. A study calendar, thorough revisions, learning the NCERT syllabus from classes 11 and 12, being familiar with question papers, and much more should all be included in the strategy. Aim for the stars! A well-documented, specific strategy considering all of your strengths and weaknesses may be really beneficial. Our team of experts have prepared study material for the students. Students must refer to the study material and tips given by our experts.

  • The first thing candidates should learn is everything, i.e., to know about the official JEE syllabus. They might compare the JEE syllabus to the syllabus for their board exams.

FAQs on Discovery of Electron, Proton and Neutron for IIT JEE

1. What is the Difference Between Protons, Neutrons, and Electrons?

Protons are positively charged subatomic particles, electrons are negatively charged particles, whereas neutrons are neutral subatomic particles. Protons and neutrons remain inside the nucleus of an atom whereas electrons rotate outside the nucleus in orbits. The mass of protons and neutrons are taken as one unit and both of them have equal mass whereas the mass of an electron is 1/2000 times of a hydrogen atom. “p” is used to denote protons, “n” is used to denote neutrons and “e” is used to denote electrons.

2. Who Discovered Electron Proton and Neutron?

The discovery of electron protons and neutrons was done by J. J. Thompson, Ernest Rutherford, and James Chadwick, respectively. Many other scientists initiated the process of discovery but were unable to conclude what these subatomic particles were. J. J. Thompson discovered electrons in 1897. Ernest Rutherford discovered protons in 1917 with the help of a gold-foil experiment. James Chadwick discovered neutrons in 1932 whereas neutrons were theorized by Ernest Rutherford in 1920. After discovering neutrons James got the Nobel prize in 1935.

3. Why Should you Learn the Discovery of Subatomic Particles?

You will come to know how subatomic particles differ in physical properties and how these properties were determined by scientists. With the help of an understanding of these particles, you will be able to lay a strong foundation for the advanced concepts of Physics, and Chemistry. By the early 1930s, it was discovered the nucleus is composed of neutrons and protons. These particles are made of different types of basic units which, together with several types of leptons constitute the fundamental building blocks.

4. What is Dalton’s theory?

The atomic theory of Dalton was the first effort to characterize all matter in terms of atoms and their characteristics. Dalton's idea was founded on the laws of mass conservation and constant composition. The theory's second portion states that all atoms of a particular element have the same mass and characteristics. According to the third section, compounds are made up of two or more different sorts of atoms. A chemical reaction, according to the fourth section of the theory, is an atom rearrangement. Because of the presence of subatomic particles and isotopes, parts of the theory had to be changed.

5. What is a gold foil experiment about?

Electrons, protons, and neutrons are the primary particles of all atoms, according to vacuum tube tests. To figure out how these fundamental particles are distributed inside the atom, several theories and tests have been presented. Thomson proposed a spherical atom model with positive charge dispersed throughout the volume and electrons arranged like plums on a cake. Rutherford attempted to experimentally discover the structure of the atom. 

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