Electronegativity

Definition

Electronegativity is the measure of an atom's ability to attract and hold onto electrons when it is part of a chemical bond. This property plays a crucial role in determining how electrons are shared or transferred between atoms, influencing the polarity of bonds and the overall reactivity of molecules.

5 Must Know Facts For Your Next Test

1. Electronegativity values are measured on a scale developed by Linus Pauling, with fluorine being the most electronegative element at a value of 4.0.
2. The electronegativity of elements typically increases across a period (left to right) and decreases down a group (top to bottom) in the periodic table.
3. Elements with high electronegativity tend to attract electrons more strongly, leading to polar covalent bonds when they bond with less electronegative elements.
4. In ionic bonds, one atom completely transfers electrons to another, typically occurring between elements with significantly different electronegativities.
5. Electronegativity is essential for predicting the behavior of molecules in chemical reactions, including their solubility, boiling point, and reactivity.

Review Questions

• How does electronegativity influence the type of bond formed between two atoms?
  • Electronegativity determines how electrons are shared or transferred between atoms during bonding. When two atoms have similar electronegativities, they tend to form nonpolar covalent bonds because they share electrons equally. If there is a significant difference in their electronegativities, an ionic bond may form where one atom completely transfers its electrons to the other, resulting in charged ions that attract each other.
• Discuss how the trends in electronegativity across the periodic table affect molecular polarity.
  • As you move from left to right across a period in the periodic table, electronegativity generally increases due to the increasing nuclear charge without significant increases in shielding. This trend means that atoms on the right side of the table, like oxygen and fluorine, will attract electrons more strongly than those on the left side, like sodium or magnesium. Consequently, when highly electronegative atoms bond with less electronegative ones, the resulting molecules exhibit polarity due to unequal sharing of electrons, which impacts their physical properties and reactivity.
• Evaluate the role of electronegativity in predicting the behavior of compounds during chemical reactions.
  • Electronegativity plays a critical role in predicting how compounds will behave during chemical reactions by influencing their bond types and molecular interactions. For instance, compounds with polar covalent bonds may react differently than those with nonpolar or ionic bonds due to their differing charges and attractions. Understanding electronegativity allows chemists to anticipate how molecules will interact with solvents and other reactants, helping them design reactions and synthesize new materials effectively.

Related terms

Ionization Energy: The energy required to remove an electron from an atom or ion, which relates to how tightly an atom holds onto its electrons.

Polar Covalent Bond: A type of chemical bond where electrons are shared unequally between two atoms, resulting in partial positive and negative charges due to differences in electronegativity.

Electropositivity: The tendency of an atom to donate electrons, which is often observed in metals that have low electronegativity.