Covalent Bonds
* Formation: Formed when two non-metal atoms share electrons to achieve a stable electron configuration (filled outer shell).
* Electron Sharing: Electrons are shared equally (nonpolar) or unequally (polar) between atoms.
* Bond Strength: Can be strong or weak depending on the type of covalent bond.
* Properties:
* Typically form molecules with low melting and boiling points.
* Poor conductors of electricity (except for graphite).
* Can be solids, liquids, or gases at room temperature.
* Often have low tensile strength.
* Examples: Water (H₂O), carbon dioxide (CO₂), methane (CH₄)
Metallic Bonds
* Formation: Formed between metal atoms where electrons are delocalized (free to move throughout the entire structure).
* Electron Sharing: Electrons are not localized between specific atoms but form a "sea" of electrons that are shared by all atoms in the metallic structure.
* Bond Strength: Generally strong due to the attraction between the positive metal ions and the sea of delocalized electrons.
* Properties:
* Excellent conductors of heat and electricity.
* Malleable (can be hammered into sheets).
* Ductile (can be drawn into wires).
* Typically have high melting and boiling points.
* Examples: Iron (Fe), copper (Cu), gold (Au)
Here's a table summarizing the key differences:
| Feature | Covalent Bond | Metallic Bond |
|--------------------|---------------|---------------|
| Atoms involved | Non-metals | Metals |
| Electron sharing | Shared between specific atoms | Delocalized, shared by all atoms |
| Bond strength | Variable | Strong |
| Conductivity | Poor | Excellent |
| Malleability | Not malleable | Malleable |
| Ductility | Not ductile | Ductile |
| Melting/Boiling Pt | Low | High |
In essence:
* Covalent bonds involve sharing electrons between specific atoms, resulting in molecules.
* Metallic bonds involve a "sea" of delocalized electrons shared by all atoms in the structure, leading to the unique properties of metals.
