1. Chemical BONDING

2. Chemical Bond A chemical bond results as atoms try to
achieve a stable octet (or duet) in their outer shell just like the noble gases

3. Two Major Types of Bonding
Ionic Bonding
forms ionic compounds
transfer of e- between valence shells
Covalent Bonding
forms molecules
sharing e- between valence shells
SALTS
Crystals

4. One other type of bonding
Metallic bonding
Occurs between atoms of a metal or MIXTURE OF METALS (alloys)
Ex. Al: aluminum foil, Cu: copper wire, Steel
Valence e- are mobile (move freely among all metal atoms)
Metallic characteristics
High m.p. temps, ductile, malleable, shiny
Good conductors of heat and electricity

5. Positive ions (nuclei)
in a sea of electrons

6. [METAL ]+ [NON-METAL ]-
Ionic Bonds form between
[METAL ]+ [NON-METAL ]-
Lost e-
Gains e-

7. also . . .
The bond to a POLYATOMIC ION
ex. KNO3
ex. NH4Cl

8. Properties of Ionic Compounds

9. Hard, angular crystals at room temp ~20oC
Form crystal lattice structures
because of alternating anions(-)
and cations (+)
Hard, angular crystals
at room temp ~20oC

10. high melting point temperatures
ex. NaCl
801oC (1,474oF)
Remember H2O melts at 0oC!
Salts & Solution PhET

11. Covalent Bonding Pairs of e- are shared between non-metal atoms H2O
NaCl

12. In covalent bonding
Electrons can be shared equally which makes the bond NON-POLAR

13. Or
Electrons can be shared Unequally which makes the bond POLAR

14. How electronegativity determines the types of bonds that form.

16. Electronegativity differences between atoms form a continuum of the types of bonds from non-polar covalent to polar covalent to ionic.
Dogs teaching chemistry

17. E-neg difference of
up to & including 0.4 = non-polar covalent (CH4) between 0.5 up to around 2.0 polar covalent (H2O)
Non-metals bonded together
METAL - Non-metal

18. Properties of Molecular Substances
Covalent
bonding
Low m.p. temp and b.p. temps
relatively soft solids as compared to ionic compounds
Poor conductors & NONconductors of electricity in any phase

19. Which are ionic and which are colavent?
Which covalents have non-polar bonds and which covalents have polar bonds?
NaH N2 KI HCl HF CsF

20. The End