| English | Electron |
|---|---|
| Bahasa Melayu | Elektron |
| 中文 | 电子 |
Definition
A stable subatomic particle carrying a negative electric charge, found orbiting the nucleus of an atom.
In exam terms
An electron is a stable subatomic particle carrying a negative charge of 1.6 × 10⁻¹⁹ C and a very small mass of about 9.11 × 10⁻³¹ kg. In electronics it is the mobile charge carrier: a flow of electrons through a conductor makes up an electric current.
Its charge is the fundamental unit of charge, symbol e.
Example of correct use: when a metal is heated, some electrons gain enough energy to leave its surface, and in a vacuum tube these free electrons are accelerated by a high voltage to form a beam.
Do not confuse it with…
Do not confuse the electron (a particle) with electric current (the rate of flow of charge, measured in amperes). Note also that conventional current is defined as flowing from positive to negative, which is opposite to the actual direction electrons drift.
In Paper 2 you may be asked to state the charge and relative mass of an electron, or to explain why heating a metal releases electrons; give the sign of the charge and remember an electron is far lighter than a proton or neutron.
Source: DSKP KSSM Physics Form 4 and 5 (Versi English) (Bahagian Pembangunan Kurikulum (BPK), KPM)