key term - Covalent bonding

Definition

Covalent bonding is a type of chemical bond where two atoms share one or more pairs of electrons, creating a strong attraction between the atoms. This sharing allows atoms to achieve a more stable electronic configuration, similar to that of noble gases. Covalent bonds can occur between nonmetals and are essential in forming molecules, influencing their structure and properties.

5 Must Know Facts For Your Next Test

1. Covalent bonds can be single, double, or triple, depending on how many pairs of electrons are shared between the atoms.
2. The strength of covalent bonds varies, with triple bonds being stronger and shorter than double bonds, which in turn are stronger than single bonds.
3. Many compounds formed through covalent bonding exhibit distinct properties such as low melting points and poor electrical conductivity compared to ionic compounds.
4. Resonance structures can occur in covalently bonded molecules, where multiple valid Lewis structures exist for the same compound, influencing its stability and reactivity.
5. Covalent bonding plays a crucial role in the formation of complex molecules such as organic compounds, which are essential for life.

Review Questions

• How does the concept of electronegativity influence the characteristics of covalent bonds?
  • Electronegativity determines how strongly an atom attracts shared electrons in a covalent bond. When two atoms with different electronegativities form a bond, the atom with higher electronegativity will pull the shared electrons closer, resulting in a polar covalent bond. This unequal sharing affects the molecule's overall polarity and influences its physical properties, such as solubility and boiling point.
• Compare the properties of covalent compounds to those of ionic compounds, particularly in terms of melting points and electrical conductivity.
  • Covalent compounds typically have lower melting points compared to ionic compounds due to weaker intermolecular forces. While ionic compounds form strong ionic bonds that result in high melting points and solid states at room temperature, covalent compounds may exist as gases or liquids with relatively low melting points. Additionally, covalent compounds usually do not conduct electricity in solid or liquid states since they do not produce free ions, whereas ionic compounds do conduct when dissolved in water or melted.
• Evaluate the significance of resonance structures in understanding the behavior of covalently bonded molecules.
  • Resonance structures are vital for illustrating how certain covalently bonded molecules can exhibit multiple valid arrangements of electron sharing. These structures reflect the delocalization of electrons across multiple atoms, leading to increased stability for the molecule. Understanding resonance helps predict reactivity patterns and molecular geometry, providing insights into chemical behavior that might not be captured by a single Lewis structure.

Related terms

Electronegativity: The tendency of an atom to attract electrons in a covalent bond, influencing bond polarity.

Molecular Geometry: The three-dimensional arrangement of atoms in a molecule, determined by the repulsions between electron pairs.

Polar Covalent Bond: A type of covalent bond where the electron sharing is unequal, leading to a partial positive charge on one atom and a partial negative charge on the other.