1. The Nonmetal-Nonmetal vs Metal – Nonmetal Bond
Covalent and
IONIC BONDING
The Nonmetal-Nonmetal
vs Metal – Nonmetal Bond

2. Lewis Dot Structures
A famous chemist named Lewis invented a symbol to show valence electrons. He used a dot next to the symbol to represent each valence electron. The dots are spread around the 4 sides.
Each pair of dots
Represents a bond.

3. Covalent Bonds
What is a Covalent Bond?
- A covalent bond is a chemical bond resulting from SHARING of electrons between 2 nonmetals. ?

4. Covalent Bonds can have multiple bonds, so you should be familiar with the following…
Single Covalent Bond- chemical bond resulting from sharing of an electron pair between two atoms. H2O
Double Covalent Bond- chemical bond resulting from sharing of two electron pairs between two atoms. CO2
Triple Covalent Bond-chemical bond resulting from sharing of three electron pairs between two atoms. N2

5. Types of Covalent Bonds
Two types of colvalent bonds: nonpolar and polar
Recall electronegativity (desire for electrons) -see shaded table on ole yeller
The electronegativity difference between the two atoms determines whether it is a nonpolar or polar bond.
Electronegativity difference:
Nonpolar Polar Ionic

6. Polar Bonds
A nonpolar bond tends to share electrons equally A polar bond means there is a dipole or one pole (end) with a positive charge and one pole (end) with a negative charge, therefore they tend to stick together better since their opposite charges attract. (=)(-) Very strong polar bonds are ionic bonds like NaCl

7. Covalent Bonds Do NOT have ions or need to Balance Charges
They use prefixes to show the number of atoms:
Mono-
Di-
Tri-
Tetra-
Examples:
H2O =
dihydrogen monoxide
CO2 = carbon dioxide
dinitrogen tetraoxide = N2O4
Phosphorus trichloride = PCl3

8. Pop Quiz: Covalent Bonds: HOT or NOT?

9. HOT, for sure!
If Miley says it’s hot, it’s HOT!

10. When a metal and nonmetal come together, a pair of electrons acts as a bond and they each become ions.

11. Ionic Bonding Rules: Metal first, nonmetal second
Nonmetal ion becomes ‘ide’
Metal is positive, nonmetal is negative
Charges must balance to zero
Formula uses a subscript to balance charges
Example: MgCl2 ; Na2O; NaCl

12. The sodium atom and chloride atom bond together as ions and form a new compound.

13. This is called an ionic bond.

14. Practice: Sodium and fluorine Barium and iodine lithium and phosphorus
Aluminum and oxygen
Beryllium and oxygen
Calcium and nitrogen

15. lithium and phosphorus
Answers:
Sodium and fluorine
sodium fluoride
NaF
Barium and iodine
barium iodide
BaI2
lithium and phosphorus
lithium phosphide
Li3P
Aluminum and oxygen
aluminum oxide
Al2O3
Beryllium and sulfur
beryllium sulfide
BeS
Calcium and nitrogen
calcium nitride
Ca3N2

16. Solutions
When ionic compounds are put in water, they dissolve into ions:

17. Polyatomic ions: are groups of atoms bonded together with a charge hence the name “poly” “atomic” “ions”.
*They behave
just like single atom
ions.
Examples:
OH-1 = hydroxide
NO3-1 = nitrate
PO4-3 = phosphate
SO4-2 = sulfate

18. Practice: Use polyatomic ions just like any other ion; But when you have more than one , use parentheses.
barium hydroxide=
(Notice parentheses show multiple ions.)

19. barium hydroxide= Ba OH +2 -1 Ba(OH)2 +2 -1(2) = 0

20. strontium nitrate =

21. strontium nitrate = Sr NO3
+2 -1
strontium nitrate = Sr(NO3)2
(2)

22. lithium phosphate

23. lithium phosphate = Li PO4
lithium phosphate Li3PO4
+1(3) + -3 = 0

24. potassium sulfate

25. potassium sulfate = K SO4
potassium sulfate = K2SO4
+1(2) + -2 = 0

26. Transition metals: Metals that have more than one possible charge:
Cobalt: Co+2, Co+3
Copper: Cu+, Cu+2
Iron: Fe+2, Fe+3
Lead: Pb+2, Pb+4
When writing the names, always use roman numerals to show the charge.

27. Examples:
Cobalt (II) Co+2, Cobalt (III) Co+3
Copper(I), Cu+, or Copper (II), Cu+2
Iron(II) Fe+2, or iron (III), Fe+3
Lead(II), Pb+2, or lead (IV), Pb+4
Each different charged ion behaves completely different than the other! The charges matter!

28. Practice!
Lead (IV) hydroxide

29. Lead(IV) hydroxide = Pb(OH)4

30. Copper (II) nitrate

31. Copper(II) nitrate = Cu(NO3)2
+2 -1

32. CoPO4

33. CoPO4 = Cobalt (III) phosphate
+3 -3

34. Fe2(SO4)3

35.
Iron (III) sulfate Fe2(SO4)3

36. Hydrates
Some ionic compounds absorb water molecules into their structures. These are called hydrates. NaCl•2H2O is the symbol for sodium chloride dihydrate. Notice the prefix di- means 2 water molecules. Name these hydrates: MgSO4•5H2O CuCl2•4H2O

37. Finding Percentage of Water in a Hydrate
You can find the percentage of water in a hydrate by dividing the mass of the water by the total mass times 100.
Lets take NaCl•2H2O
Using the periodic table, the mass of Na=23, Cl=35.5, H2O = 18. Total mass with 2 H20 is 94.4
Water mass (36)/ Total (94.4) x 100
= 38 % water

38. What are the differences between ionic bonding and covalent bonding
What are the differences between ionic bonding and covalent bonding? List them below:

39. Differences: Ionic Metal , nonmetal-ide
Balance charges using subscripts
Polyatomic ions use parentheses in multiples
Transition metals use roman numerals to show charge

40. Differences: Covalent Two nonmetals Nonmetal, nonmetal-ide
No ions- they share e-
Use prefixes
Don’t need to balance

41. Differences: Ionic Metal , nonmetal-ide
Balance charges using subscripts
Polyatomic ions use parentheses in multiples
Transition metals use roman numerals to show charge
Covalent
Two nonmetals
Nonmetal, nonmetal-ide
No ions- they share e-
Use prefixes
Don’t need to balance

42. Ionic bonds: HOT or NOT?

43. Definitely HOT Baby!

44. The End!