Electronegative

Definition

Electronegativity is a chemical property that describes the ability of an atom to attract shared electrons in a chemical bond. Atoms with high electronegativity values are considered electronegative, meaning they have a strong tendency to attract and hold onto electrons.

5 Must Know Facts For Your Next Test

1. Electronegative atoms tend to have a high number of valence electrons and a small atomic radius, which contributes to their strong electron-attracting ability.
2. The difference in electronegativity between bonded atoms determines the degree of polarity in a covalent bond, with a larger difference resulting in a more polar bond.
3. Highly electronegative atoms, such as fluorine, chlorine, and oxygen, often form polar covalent bonds with less electronegative atoms, like hydrogen or sodium.
4. Electronegativity plays a crucial role in understanding the formation of Lewis structures and predicting the formal charges of atoms in a molecule.
5. Resonance structures can be used to distribute formal charges more evenly among electronegative atoms in a molecule, minimizing the overall formal charge.

Review Questions

• Explain how electronegativity influences the formation of Lewis structures.
  • The electronegativity of atoms is a key factor in determining the distribution of shared electrons in a molecule, as depicted by Lewis structures. Atoms with higher electronegativity values will attract the shared electrons more strongly, resulting in a greater electron density around them. This unequal distribution of electrons leads to the formation of polar covalent bonds, where one atom bears a partial positive charge and the other a partial negative charge. Understanding electronegativity is essential for correctly drawing Lewis structures and predicting the arrangement of atoms in a molecule.
• Describe the relationship between electronegativity and formal charges in resonance structures.
  • Formal charges in a molecule are influenced by the electronegativity of the atoms involved. Electronegative atoms, such as oxygen and fluorine, tend to have a greater ability to attract shared electrons, resulting in a partial negative charge. Conversely, less electronegative atoms, like hydrogen and sodium, will have a partial positive charge. In resonance structures, the formal charges can be distributed more evenly among the electronegative atoms, minimizing the overall formal charge of the molecule. This is achieved by considering the relative electronegativity of the atoms and adjusting the placement of shared electrons accordingly.
• Analyze how the difference in electronegativity between bonded atoms affects the polarity and reactivity of a molecule.
  • The difference in electronegativity between bonded atoms is a key factor in determining the polarity of a covalent bond and the overall reactivity of a molecule. When there is a significant electronegativity difference, the shared electrons are unequally distributed, resulting in a polar covalent bond with a partial positive and partial negative charge. This polarity can influence the molecule's reactivity, as the partially charged regions can participate in various chemical interactions, such as hydrogen bonding, dipole-dipole interactions, or ionic interactions. Molecules with highly polar bonds, due to a large electronegativity difference, tend to be more reactive and participate in a wider range of chemical reactions compared to non-polar or less polar molecules.

Related terms

Electropositive: The opposite of electronegative, electropositive atoms have a low tendency to attract shared electrons and instead readily donate electrons in chemical bonds.

Polar Covalent Bond: A covalent bond where the shared electrons are unequally distributed due to the difference in electronegativity between the bonded atoms, resulting in a partial positive and partial negative charge.

Pauling Electronegativity Scale: A scale developed by Linus Pauling that assigns a numerical value to the electronegativity of each element, with fluorine having the highest value of 4.0.