Definition

Noun: A soft, grey, malleable metallic element that resembles tin but discolors on exposure to air. It is highly toxic and is used in rodent and insect poisons. It occurs in zinc blende and some iron ores. This is the scientific term for the chemical element thallium.

Usage

This term is used primarily in scientific, technical, and academic contexts to specify the element with 81 protons in its nucleus. * The atomic number 81 defines the element's identity and its position on the periodic table. * Due to its toxicity, compounds containing atomic number 81 require careful handling.

Examples

• In chemistry class, we learned that atomic number 81, thallium, is located in group 13 of the periodic table.
• The forensic report indicated traces of atomic number 81 in the sample, pointing to a specific type of poison.
• The mineral contains small amounts of atomic number 81 as an impurity.

Advanced Usage

• The term is used unambiguously in scientific literature to avoid confusion with element symbols or common names. For example: "The isotope of interest was that of atomic number 81."

Variants and Related Words

• Thallium (Tl): The common name and chemical symbol for atomic number 81.
• Element 81: A synonymous informal term.

Synonyms

• Thallium
• Tl (chemical symbol)
• Element 81

Notes on Meaning

This term has only one specific meaning: it is the definitive identifier for the chemical element thallium based on the number of protons in its atomic nucleus. It is not used in idiomatic or figurative language.

Noun

1. a soft grey malleable metallic element that resembles tin but discolors on exposure to air; it is highly toxic and is used in rodent and insect poisons; occurs in zinc blende and some iron ores