Definition

Noun An electron that is located in the outermost shell (valence shell) of an atom. These electrons are involved in the formation of chemical bonds with other atoms.

Usage

The term "valence electron" is used to describe the specific electrons responsible for an atom's chemical properties and bonding behavior. It is a core concept in chemistry.

Examples

• The number of valence electrons determines an element's position in the periodic table.
• Sodium has one valence electron, which it readily donates to achieve a stable electron configuration.
• Oxygen needs two more valence electrons to complete its outer shell.

Advanced Usage

• Valence electron count: The total number of electrons in the outermost shell. This count is crucial for predicting an atom's reactivity and the types of bonds it will form (ionic or covalent).
• Delocalized valence electrons: In metals, valence electrons are not bound to a single atom but are free to move throughout the structure, explaining properties like electrical conductivity.

Variants and Related Words

• Valence shell (n): The outermost electron shell of an atom.
• Valency (n): The combining power of an element, often related to the number of valence electrons it can share, lose, or gain.

Synonyms

• Outer-shell electron
• Bonding electron

Related Phrases

• Core electron: An electron that is not a valence electron; it is located in an inner shell and does not typically participate in bonding.

Noun

1. an electron in the outer shell of an atom which can combine with other atoms to form molecules