Electrons

what is an electron?

An electron is a subatomic particle with a negative electric charge. Electrons are found in orbitals or energy levels surrounding the nucleus of an atom.

basic properties

• symbol: e⁻
• charge: -1
• mass: ~1/1836 of a proton
• location: outside the nucleus, in electron shells

discovery

j.j. thomson discovered the electron in 1897 using cathode ray tube experiments. This was the first subatomic particle ever identified.

role of electrons

• Balance the charge of protons in atoms
• Involved in all chemical reactions and bonding
• Define the ion state of an atom (e.g., losing or gaining electrons)
• Determine the electron configuration and properties of elements

electrons and chemical bonding

Electrons in the outer shell (valence electrons) are key to:

• covalent bonds
• ionic bonds
• metallic bonds

electron cloud model

Instead of fixed orbits, modern quantum theory describes electrons as existing in a cloud of probabilities around the nucleus.

see also

• protons
• neutrons
• nucleus
• electron configuration
• valence electrons
• j.j. thomson

disclaimer

This article is intended for educational and academic use only and supports learning in chemistry and physics within a MediaWiki-based environment.