BONDING
Bonds Between Atoms
Covalent
Ionic
MoleculesNetwork
Metallic
Metallic Bonding
Metals lose their outer electrons easily and become cations
creating a “sea” of electrons to roam freely around the metal cations.
The strong electrostatic attraction between cations and roaming electrons explains why:
• metals conduct electricity• are extremely strong and
hard to break• Can be bent and stretched• Have high melting points
Malleable and Ductile
The mobile electrons will shift to adjust to new arrangements around positive ions. They act as the "glue".
Ionic Bonding
Ionic Bonds
- results from the TRANSFER of electrons from a metal to a non-metal
Ions are held strongly by electrostatic forces in a 3D lattice
Properties
1.Have high melting points because of strong electrostatic attractions between cations and anions
2.Soluble in water
3. Conducts electricity if dissolved in water (has free ions) but not in solid state
4. Brittle – similar ions can repel when disturbed
Covalent Molecules
Covalent Molecular
- When 2 or more non-metals SHARE electrons; no charged ions are formed
- Does NOT form large lattices
- forms small, neutral molecules that are weakly attracted to other molecules
Forces
Properties:
1.Weak forces between molecules means that it has low melting points.
2.Does not conduct electrical current
Covalent Network
Covalent Network Solids
•when either carbon or silicon atoms are bonded covalently to form an infinite 3-D lattice
•network solids are extraordinarily strong
Diamond
•Each Carbon atom bonds to 4 others
•Strong covalent bonds throughout
•High melting points
•does not conduct electricity.
Silicon Dioxide: Sand & Quartz
• SiO2