electronegativity

Thân thiện

A student studies a periodic table showing electronegativity values.

Definition

1. Noun:
   • (Chemistry): A measure of the tendency of an atom or a functional group to attract electrons (or electron density) towards itself when forming a chemical bond. It is a dimensionless property that helps predict the polarity of bonds and the distribution of charge within molecules.

Usage

• General Concept: Electronegativity is a fundamental concept used to explain why certain atoms form ionic bonds while others form covalent bonds. It is a comparative scale, with fluorine assigned the highest value.
• In Sentences: The term is used as a singular, uncountable noun when referring to the general property, but can be countable when comparing specific values (e.g., "the electronegativities of oxygen and nitrogen").

Examples

• Noun:
  • Fluorine has the highest electronegativity on the Pauling scale.
  • The difference in electronegativity between two atoms determines the bond type.
  • Oxygen's high electronegativity makes it a strong oxidizing agent.

Advanced Usage

• "Electronegativity difference": A key parameter for predicting bond character. A large difference (> ~1.7) often indicates an ionic bond, while a small difference indicates a covalent bond.
  • The large electronegativity difference between sodium and chlorine results in the formation of an ionic compound, NaCl.
• "Electronegativity scale": Refers to the numerical scales (e.g., Pauling scale, Mulliken scale, Allred-Rochow scale) devised to quantify this property.
  • On the Pauling electronegativity scale, values range from about 0.7 for cesium to 4.0 for fluorine.

Variants and Related Words

• Electronegative (adj): Having a high tendency to attract electrons.
  • Chlorine is a highly electronegative element.
• Electropositivity (n): The opposite tendency, referring to an atom's tendency to donate electrons.

Synonyms

• Electron affinity (Note: This is a related but distinct concept measuring the energy change when an electron is added to a neutral atom).
• Electron-attracting power (descriptive synonym).

Related Phrases and Concepts

• Periodic trend: Electronegativity generally increases across a period (left to right) and decreases down a group in the periodic table.
• Polar covalent bond: A bond formed between atoms with a moderate difference in electronegativity, resulting in an uneven sharing of electrons.

Học thuật

Noun

1. (chemistry) the tendency of an atom or radical to attract electrons in the formation of an ionic bond

Từ đồng nghĩa

• negativity