Definition

Noun: 1. Lanthanum: A soft, malleable, silvery-white metallic element that is the first element in the lanthanide series. It tarnishes rapidly when exposed to air and is found in various rare-earth minerals.

Usage Notes

• "Atomic number 57" is the scientific and technical term used to uniquely identify the element Lanthanum in chemistry and physics. The atomic number defines the number of protons in an atom's nucleus.
• In most general and chemical contexts, the element is referred to by its name, lanthanum.

Examples

• Scientific Context:
  • The element with atomic number 57 is a key component in hybrid car batteries.
  • On the periodic table, atomic number 57 corresponds to the element Lanthanum.
• Definitional Context:
  • Lanthanum, or atomic number 57, is often used in high-quality camera lenses.

Advanced Usage

• The notation is often seen in formulas, tables, and technical literature. For example: "Elements with atomic numbers 57 through 71 are known as the lanthanides."

Variants and Related Words

• Lanthanum (n): The common name for the element with atomic number 57. Symbol: La.
• Rare-earth element (n): A classification that includes lanthanum and the other lanthanides, along with scandium and yttrium.
• Lanthanide (n): Any of the series of 15 metallic elements from atomic number 57 (lanthanum) to 71 (lutetium).

Synonyms

• Lanthanum (This is the primary synonym, not a different word but the element's name).
• Element 57 (A less formal technical synonym).
• La (The chemical symbol).

Related Phrases

• Atomic number: The number of protons in the nucleus of an atom, defining the chemical element.
• Periodic table: The tabular arrangement of chemical elements ordered by atomic number.

Noun

1. a white soft metallic element that tarnishes readily; occurs in rare earth minerals and is usually classified as a rare earth