Discovery of electron

Introduction

The electron is a negatively charged, low-mass particle. When moving close to other electrons or the positive nucleus of an atom, it may be easily deflected as a result of this effect.

The first fundamental particle found was the electron. J.J. Thomson is credited with discovering the electron and its properties through studies conducted in a discharge tube. Electrons, he believed, are necessary components of all atoms. J.J. Thomson experimented with a gas at a low pressure of 0.01mm Hg in a discharge tube.

Electron Characteristics

The atom is the smallest constituent of matter. The nucleus is at the centre of the atom, surrounded by one or more electrons. The nucleus is made up of protons and neutrons, which are collectively known as nucleons. Protons have a mass of 1.00867 amu while neutrons have a mass of 1.00728 amu, making them the most massive of the elements. Protons are electrically neutral particles having a mass of 1.00867 amu and an electrically neutral charge.

Electrons have a mass of 0.000549 amu and are negatively charged particles. Electrons are 1836 times heavier than protons and neutrons.The neutral atom is formed when the number of electrons equals the number of protons. The electronic arrangements of an element define its chemical properties, but the nuclear structure defines the stability and radioactive transition of the atom.

Fundamental Particles – Electrons

Electrons are fundamental particles.

J.J.Thomson experimented with a gas at a low pressure of 0.01mm Hg in a discharge tube. A discharge tube is a long glass tube with two metal plates connected to the oppositely charged poles of the battery. Cathode and anode are the terms for the metal plates that make up the cathode and anode, respectively. When a high voltage is applied to a gas, it ionises it, resulting in the ejection of negatively charged particles known as electrons. These particles are created by cathode rays.

Goldstein anticipated the presence of positively charged particles in an atom based on the atom’s electrical neutrality. The discovery of protons by Goldstein, based on the electrical neutrality of an atom. Goldstein used the cathode ray experiment in his discovery of protons. The anode was discovered to emit positively charged ions as a result of electron ejection. These rays are referred to as anode rays or canal rays. Anode rays or canal rays are a stream of positively charged particles. Protons were revealed to be the anode rays created by hydrogen gas in a discharge tube.

The discovery of electrons and protons as subatomic particles within the atom led to the development of atomic models that portray the arrangement of the fundamental particles within an atom.

Configuration of electrons

• The electron configuration describes how electrons are grouped in energy levels or shells around the nucleus. The electrons in an atom inhabit the innermost available shells, which have the lowest available energy levels.
• A maximum of two electrons can be found in the first level or shell.
• After that, the energy levels or shells can only accommodate a maximum of 8 electrons.
• The electronic configuration is expressed as a series of integers, such as 2, 6 for oxygen and 2, 8, 3 for aluminium.
• The elements are arranged in the periodic table according to their electrical structure. The outermost shell of all elements in the same group has the same number of electrons. As a result, elements in the same group exhibit similar qualities. A specific energy level is gradually filled with electrons from left to right across each cycle. The next energy level is filled in the next session, and so on.

Conclusion 

• All atoms include electrons, which are small negatively charged subatomic particles discovered by J.J. Thomson while working with cathode ray tubes in the 1930s.
• In Thomson’s plum pudding atom model, negatively charged electrons were immersed within a positively charged “nucleus.”
• Rutherford’s gold foil experiment proved that the atom is basically empty space with a little, dense, positively charged nucleus at its centre.
• Based on these observations, Rutherford proposed the nuclear model of the atom.