CBSE Class 9 Answered

Properties of Electrons

• An electron, which is denoted as e^-, is the fundamental particle with a negative charge.
• Its properties are independent of the gas in the discharge tube.
• The mass of an electron is negligible and its charge is -1.
• The mass of an electron is extremely small. It is  of the mass of a hydrogen atom (9.108 × 10^-28 g) and so its mass is considered almost negligible. (Hydrogen is an atom of the lowest mass). Since the mass of a hydrogen atom is 1 u, we can say that the relative mass of an electron is u.
• The absolute mass of an electron is 9 × 10^-28 grams.
• Its charge is 1 unit negative charge, i.e. 1.602 × 10^-19 coulombs.
• The tiny electrons revolve around the nucleus of the atom in specific orbits or shells.