Ionic Bonds
- Nature of Bond: Electrons are transferred, not shared.
- Participants: Typically between one metal and one nonmetal, resulting in oppositely charged ions.
- Bond Strength: Electrostatic interactions hold the ions together.
Ionic Solids
- Solid at room temperature due to strong ionic bonds.
- High boiling points.
- Highly ordered crystal lattice structure:
- Not malleable due to lack of give.
- Solubility: At least slightly soluble in water.
- Conductivity:
- Cannot conduct electricity in solid form.
- Conducts electricity as a liquid or in aqueous solution (ions are free to move).
Covalent Bonds
- Nature of Bond: Electrons are shared.
- Participants: Generally occurs between two atoms with high ionization energies (commonly two nonmetals).
Non-Polar Covalent Bonds
- Definition: Atoms have less than a 0.4 ; electrons are shared equally.
- Properties:
- Use London dispersion forces (LDF).
- Low melting and boiling points.
- Often gases at room temperature due to weak intermolecular forces.
- Larger molecules (e.g., wax) can be solid at room temperature.
- Do not conduct electricity (no ions).
Polar Covalent Bonds
- Definition: is between 0.4 and 1.7; electrons favor the atom with the higher .
- Properties:
- Stronger intermolecular forces than non-polar covalent (dipole-dipole forces; sometimes hydrogen bonding).
- Dissolve in polar solvents if hydrogen bonding is present (e.g., sugar in water).
Coordinate Covalent Bonds
- Definition: Both shared electrons come from the same atom.
Metallic Bonds
- Nature of Bond: Forms between two metals.
- Participants: Atoms with low ionization energies and low electronegativities.
- Structure:
- Positive nuclei in a lattice surrounded by delocalized electrons.
- Electron Behavior: Electrons are delocalized, allowing for unique metallic properties.
- Properties:
- Malleable and ductile due to the unrestricted movement of delocalized electrons.
- Good conductors of heat and electricity due to delocalized electrons.
- Shiny: Light excites valence electrons, which absorb energy, oscillate, and reemit it.
- Exhibit the photoelectric effect.
Network Solids
- Definition: Macromolecules with giant covalently bonded structures in 1D, 2D, or 3D arrays.
- Bond Strength: Covalent bonds are stronger than ionic bonds.
- Properties: Depend on dimensional structure.
Allotropes
- Definition: Different physical forms of the same element.
Dimensional Structures
-
3D Network Solids:
- Extremely strong bonds result in very high melting and boiling points.
- Extremely hard and not soluble.
- Examples: Diamond, quartz, silicon carbide.
-
2D Network Solids:
- Layers of 2D sheets with high melting and boiling points but softer structures.
- Conduct electricity slightly due to delocalized double bonds.
- Example: Graphite.
-
1D Network Solids:
- Form fibers with high melting and boiling points.
- Examples: Asbestos.
Examples of Network Solids
- Silicon compounds, mica, asbestos.
Atomic structures
- bonds moving is only electricity conductive if the bonds move around OUTSIDE of the electrons
- when calculating formal charges, count bonds as one, when calculating if it’s valance shell is full, count as two