Electron
Definition and meaning of Electron in chemistry.
An electron is a stable, tiny subatomic particle that carries a negative electric charge. These particles exist in specific probability zones called orbitals outside an atom's central nucleus. Electrons drive all chemical reactions because they control how atoms bond together.
In more detail
Electrons are elementary particles, meaning they contain no smaller pieces. They belong to a group of physics particles called leptons. Inside an atom, the positive protons in the nucleus strongly attract the negative electrons.
This electrical pull keeps the electrons in their specific energy shells and subshells. Strict quantum rules control exactly how electrons fill up these energy shells. These rules include the Aufbau principle, the Pauli exclusion principle, and Hund's rule.
This organized filling pattern perfectly matches the layout of the periodic table. Chemical bonding depends almost entirely on an atom's valence electrons. Valence electrons are the ones sitting in the atom's outermost energy shell.
Atoms constantly share or trade these outer electrons to reach lower energy states. An electron weighs almost nothing, about 1/1836 the mass of a proton. Despite being tiny, their movement controls everything from forming rust to emitting light.
Free electrons flowing through a metal wire create the electricity that powers electronics. Many people wrongly picture electrons as tiny, solid balls spinning like planets. In reality, they act as fuzzy probability clouds behaving as particles and waves simultaneously.
Key facts
| Symbol | e⁻ |
|---|---|
| Charge | -1 elementary charge (-1.602 × 10⁻¹⁹ C) |
| Relative mass | ~1/1836 of a proton (9.109 × 10⁻³¹ kg) |
| Particle classification | Elementary fermion (lepton) |
| Primary role | Governs chemical bonding and electromagnetic interactions |
A neutral sodium atom has exactly 11 electrons orbiting its central nucleus. Its final valence electron sits all alone in the outermost 3s orbital. The sodium atom eagerly gives this outer electron to a chlorine atom during a reaction. This trade creates stable Na+ and Cl- ions with full outer shells. These ions instantly snap together to form a solid crystal of table salt. This single electron transfer turns two dangerous chemicals into a biologically essential salt.
Frequently asked questions
Who discovered the electron?
Physicist J. J. Thomson discovered the electron in 1897 using cathode-ray tube experiments. He proved that atoms contain negatively charged particles that are far lighter than the atom itself.
What is a valence electron?
A valence electron is an electron located in an atom's outermost energy shell. These specific electrons form chemical bonds and determine how an element reacts with other chemicals.
How do electrons relate to light and color?
When an atom absorbs energy, its electrons jump to higher energy levels. When they fall back down to their normal state, they release that energy as a photon of light.