Definition

Noun: * Argon: A chemical element (symbol Ar) that is a colorless, odorless, and non-reactive (inert) noble gas. It is one of the six naturally occurring noble gases and makes up a significant portion (about 0.934%) of Earth's atmosphere.

Usage

• The term "atomic number 18" is a precise scientific identifier for the element argon. It is used primarily in technical, chemical, and educational contexts to specify the element based on its number of protons.
• Example: "The gas used to fill the window's insulating space is atomic number 18, which is more effective than air at preventing heat transfer."

Advanced Usage

• In scientific writing, the atomic number is often used in tables, classifications, or when discussing periodic trends. The element's common name, "argon," is used in most other contexts, including its industrial applications.
• Example: "Elements with full electron shells, like atomic number 18 (argon), are exceptionally stable and unreactive."

Variants and Related Words

• Argon (n): The common name for the element with atomic number 18.
• Noble gas (n): The family or group of elements to which argon belongs, characterized by their lack of chemical reactivity. Other members include helium (atomic number 2) and neon (atomic number 10).
• Inert gas (n): A term often used interchangeably with "noble gas," emphasizing its non-reactive property.

Synonyms

• Argon: This is the direct and most common synonym.
• Inert gas: A descriptive synonym highlighting its key chemical property, though this term can also refer to other noble gases.

Related Phrases/Idioms

• (This term is a technical scientific identifier and is not used in idiomatic expressions or common phrasal verbs.)

Noun

1. a colorless and odorless inert gas; one of the six inert gases; comprises approximately 1% of the earth's atmosphere