An atom as a whole is electrically neutral. In the year 1897, J.J. Thomson discovered the electron with his experiment with a cathode ray tube. He said that the cathode rays that travel in the tube from the cathode to the anode are negatively charged subatomic particles called electrons. According to his model, atoms are positively charged spheres with electrons embedded in them. Later, scientists discovered the fundamental subatomic particles called protons and neutrons.
Neil Bohr proposed his quantised shell model of the atom. According to the Bohr atom model, electrons revolve around the nucleus in stable orbits. Radiation is emitted when these electrons jump from one orbit to another. The important properties of electrons are listed below.
8 Properties of Electrons
Property 1: Electrons are negatively charged particles.
Property 2: The mass of the electron is 1/2000 times lesser than the mass of proton and neutron. Therefore, the electrons do not contribute to the mass of the atom.
Property 3: An electron has an electric charge of – 1(-1.602 × 10-19 coulombs) which is equal and opposite to the charge of a proton, which is +1.
Property 4: Electrons are subatomic particles found outside the nucleus, unlike protons and neutrons, which are present inside the nucleus.
Property 5: According to the Bohr atom model, electrons are continuously moving around the nucleus in orbits or shells.
Property 6: The invariant mass of an electron is approximately 9.109×10−31 kilograms.
Property 7: Electrons display both particle properties and wave properties.
Property 8: According to the principle of quantum mechanics, position and momentum of the electrons cannot be determined simultaneously.