Achievements of Scientists

Atoms are the basic unit of all things that are present in our universe. To our astonishment, even on solid surfaces and during the collision of two bodies two atoms never touch each other. Atoms consist of negatively charged subatomic particles, electrons, positively charged protons, and neutrally charged particles neutrons. This structure of atoms, along with its subatomic particles and the discovery of those subatomic particles, was itself a great discovery. These significant particles are at a size of 100 picometers in surface area. These atoms have one centrally placed nucleus with all its positive charges concentrated at the centre with all its negative charges revolving around the nucleus. Atom was discovered even in ancient times before John Dalton by Indian and Greek scientists as “anu parmanu. “

Discovery of the Atom and Subatomic Particles

Dalton discovered that when a chemical compound mixes with another compound, it produces another compound. The chemical compound which is added always combines at a certain fixed fraction at all times. This property is defined by John Dalton under the law of multiple proportions. This property is sought by other fellow scientists for gaseous substances to elaborate their properties under the Kinetic theory of gases. There then happened the discovery of subatomic particles.

 J J Thompson discovered when he passed a group of rays in a cathode experiment, and there was a deflection of rays from certain particles. He called these particles corpuscles. These are later known as electrons. He also stated that these particles deflected rays that are 1800 times lighter than hydrogen particles. So this allowed him to prove that there are certain smaller particles inside an atom. He also proposed that atoms have electrons arranged in a pudding or watermelon model. The watermelon seeds present represent the electrons present in atoms.

This was disproved by another scientist Ernst Rutherford. He took an experiment to measure the charge to mass ratio of alpha rays. Here he concentrated alpha rays towards the atoms, but unfortunately, his experiment was difficult due to the scattering of rays. This difficulty was also present in Thompson’s experiment, but he used a vacuum, and he had minimal deflection at most. Rutherford prepared a set of experiments where he had an aim to find out the reason for the deflection of rays. So he again did his alpha ray scattering experiment. 

During this experiment, he had one ray with sharp 90-degree deflection. To deflect such a heavy ray, there should be a heavy positive charge present at that point. Then he postulated about the presence of a heavy nucleus with neutrons and protons. This nucleus is equally positively charged like electrons present in atoms to maintain circulation. 

Scientists named Frederick Soddy discovered that there can be atoms with more than one atomic weight and can share a place in the periodic table. These are called isotopes by Margaret Todd.

Niels Bohr came up with an idea to define that electrons rotate around the nucleus. An electron cannot rotate continuously. If it does, it falls into the nucleus and causes the collapse of atoms. This destroys substances. Instead, Niels Bohr postulated that electrons rotate around certain energy consisting of orbits called orbitals. These orbitals have a certain energy. When an electron jumps from one energy level to another, that is, from one orbital to another, there happens emission of kinetic energy in the form of electromagnetic radiation. This also supports the theory of conservation of energy.

Soon Werner Heinrich and Erwin Schrodinger discovered the principle of uncertainty where he used silver rays to find the atomic structure. He described the structure through the quantum numbers of atoms. They both separately found out that the momentum and position of particles vary from time to time, and they also postulated formulas to find out the quantum numbers of a particular atom at a particular time. Erwin Schrodinger discovered his Schrodinger formula that supports the field of electron rotation in terms of waves rather than particles in two dimension 

Conclusion

This article describes the discovery of atoms, subatomic particles, and the structure of atoms. This structure of the atom helps in lots of inventions such as atomic bombs, nuclear fission, nuclear fusion., etc. This discovery helps to analyse the physics behind atomic energy and electromagnetic radiation. The Discovery of neutrons happened in response to the weight imbalance that happened when the weight of an element was calculated along with electrons and protons. Then happened the discovery of the neutrons, a non-charged particle present in the atom to balance weight.