1. Ionic, Metallic, & Polar Covalent Bonds
Describe how metals bond and form alloys
Describe how Atoms bond to each other

2. Metallic Bonds and Properties
Metallic bonds form between metal elements
The valence electrons of metal atoms can be modeled as a sea of electrons
The electrons are mobile and can drift from one part of the metal to another
This is how electricity works

3. Alloys
A combination of metals or a metal and another element. Often done to increase material strength or to help resist corrosion
The properties of alloys are often better than those of their component elements
Examples:
Sterling silver (silver and copper) is more durable than pure silver
Steels (iron, carbon, boron, chromium etc) resist corrosion, have better ductility, hardness, and toughness

4. Formation of Ionic Compounds
Ionic compounds form when a metal transfers one or more electrons to a nonmetal.
Ionic compounds are two or more elements held together by opposite charge attraction.
Ionic compounds are composed of cations and anions, usually a metal cation and nonmetal anion.
Are electrically neutral
The Difference in electronegativity of ionic bonded atoms is greater than 2

5. Bond Character Example-Fluorine
Atoms: NaCl
Electron Movement:
Electronegativity Difference: =_____
Bond Type:

6. Properties of Ionic Compounds
Crystalline Solids (at room temp)
High Melting Point
Conduct an electric current when melted or dissolved in water
Made up of a metal and non metal
Generally a brittle solid
Most ionic compounds are crystalline solids at room temperature
They have a regular repeating 3-D patterns
Ionic compounds generally have high melting points

7. Covalent Compounds Formation Properties
Covalent compounds are formed when two or more nonmetals share electrons.
Generally insoluble in water
Non conductive
Can be solid, liquid, or gas
Made up of non metals

8. Bond Polarity
Nonpolar covalent bonds form when bonding electrons are shared equally
Diatomic molecules are nonpolar
Difference in electronegativity of bonded atoms is between 0 & .4
Polar covalent bond, or a polar bond, is a bond between atoms in which the electrons are shared unequally
The more electronegative atom attracts electrons and gains a slight negative charge, the less electronegative atom gains a slightly positive charge.
Difference in electronegativity of bonded atoms is between .4 & 2
Example: Water

9. Bond Character Example-Fluorine
Molecule: F2
Electron Movement:
Electronegativity Difference: =_____
Bond Type:

10. Bond Character Example-Fluorine
Molecule: H2O
Electron Movement:
Electronegativity Difference: =_____
Bond Type:

11. Molecule Shapes
Molecular Geometry: The arrangement of atoms within a given molecule.
VSEPR: Valence Shell Electron Pair Repulsion
Is based on simple electrostatic repulsions of electron pairs
Assumption: Electrons in chemical bonds( single, double, or triple) and unshared electron pairs are negative centers that repel each other

12. VSEPR Shapes Shape Atoms Bonded Electron Regions Example Linear 2 Bent
3 or 4
Trigonal Planar 3
Trigonal Pyramidal 4
Tetrahedral

13. VSEPR Theory Valence Shell Electron-Pair Repulsion
Repulsion between electron pairs causes molecular shapes to adjust so that the valence-electron pairs stay as far apart as possible

14. Attractions Between Molecules
Van der Waals Forces consist of dipole interactions and dispersion forces
Weakest attractions between molecules
Dipole interactions occur when polar molecules are attracted to one another
Dispersion forces occur when moving electrons in a nonpolar molecule are momentarily more on one side than other. Momentary dipole

15. Hydrogen Bonds
Attractive forces in which a hydrogen which is covalently bonded to a very electronegative atom is also weakly bonded to an unshared electron pair of another electronegative atom.

16. Network Solid
A solid in which all of the atoms are covalently bonded to each other
Examples: Diamond and Silicon carbide

17. Molecular Orbitals
Sigma bonds form when 2 atomic orbitals combine, forming a symmetrical orbital around an axis
Pi bonds form when p orbitals overlap end-to-end forming sausage-shaped regions above and below the bond axis