Definition

1. Noun:
   • A chemical element: "atomic number 40" is the scientific designation for the metallic element zirconium (symbol Zr). It refers to the element's specific position (40) in the periodic table, indicating it has 40 protons in its atomic nucleus.

Usage

• The term "atomic number 40" is used primarily in scientific, technical, and educational contexts to precisely identify the element zirconium by its fundamental property (proton count), rather than its common name.
• It is a formal and unambiguous identifier in chemistry and physics.

Examples of Usage

• Noun:
  • The alloy contained a trace amount of atomic number 40. (This specifies the element zirconium is present.)
  • Elements are ordered on the periodic table by their atomic number; atomic number 40 is zirconium.

Advanced Usage

• In nuclear contexts: The property of "atomic number 40" (zirconium) as a neutron absorber is critical in nuclear engineering.
  • The control rods were clad in a metal containing atomic number 40 for its neutron absorption properties.

Variants and Related Words

• Zirconium (n): The common name for the element with atomic number 40.
• Zr (n): The chemical symbol for atomic number 40 / zirconium.
• Baddeleyite (n): A mineral that is a source of atomic number 40 (zirconium oxide).
• Zircon (n): A common mineral (zirconium silicate) that is a chief source of atomic number 40.

Synonyms

• Zirconium: The direct and most common synonym for "atomic number 40".

Related Scientific Terms

• Transition metal: "Atomic number 40" (zirconium) is classified as a transition metal.
• Neutron absorber: A key functional property of atomic number 40 in nuclear applications.

Noun

1. a lustrous grey strong metallic element resembling titanium; it is used in nuclear reactors as a neutron absorber; it occurs in baddeleyite but is obtained chiefly from zircon