Upload
saoirse-plunkett
View
79
Download
1
Tags:
Embed Size (px)
DESCRIPTION
IONIC BONDING. The Metal – Nonmetal Bond. 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. - PowerPoint PPT Presentation
Citation preview
The Nonmetal-Nonmetal
vs Metal – Nonmetal Bond
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.
Covalent Bonds•What is a Covalent Bond?
- A covalent bond is a chemical bond resulting from SHARING of electrons between 2 nonmetals.
•?
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
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:
0 .4 2.0
Nonpolar Polar Ionic
Polar BondsA 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
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
Pop Quiz: Covalent Bonds:HOT or NOT?
HOT, for sure!If Miley says it’s hot, it’s HOT!
When a metal and nonmetal come together, a pair of electrons acts as a
bond and they each become ions.
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
The sodium atom and chloride atom bond together as ions and form a new
compound.
This is called an ionic bond.
Practice:Sodium and fluorine
Barium and iodine
lithium and phosphorus
Aluminum and oxygen
Beryllium and oxygen
Calcium and nitrogen
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
Solutions
• When ionic compounds are put in water, they dissolve into ions:
Polyatomic ions: are groups of atoms bonded together with a charge hence the name “poly”
“atomic” “ions”. • Examples:
• OH-1 = hydroxide
• NO3-1 = nitrate
• PO4-3 = phosphate
• SO4-2 = sulfate
*They behavejust like single atom
ions.
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.)
barium hydroxide= Ba OH
+2 -1
Ba(OH)2
+2 -1(2) = 0
• strontium nitrate =
• strontium nitrate = Sr NO3
+2 -1
strontium nitrate = Sr(NO3)2
+2 + -1(2)
• lithium phosphate
• lithium phosphate = Li PO4
+1 -3
lithium phosphate Li3PO4
+1(3) + -3 = 0
potassium sulfate
• potassium sulfate = K SO4
+1 -2
potassium sulfate = K2SO4
+1(2) + -2 = 0
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.
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!
Practice!
Lead (IV) hydroxide
• Lead(IV) hydroxide = Pb(OH)4
• Copper (II) nitrate
• Copper(II) nitrate = Cu(NO3)2
+2 -1
• CoPO4
• CoPO4 = Cobalt (III) phosphate
+3 -3
• Fe2(SO4)3
+3 -2Iron (III) sulfate Fe2(SO4)3
HydratesSome 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
Finding Percentage of Waterin 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
What are the differences between ionic bonding and covalent bonding? List them below:
Differences:
Ionic• Metal , nonmetal-ide• Balance charges using
subscripts• Polyatomic ions use
parentheses in multiples• Transition metals use
roman numerals to show charge
Differences:
Covalent• Two nonmetals• Nonmetal, nonmetal-
ide• No ions- they share e-• Use prefixes• Don’t need to balance
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
Ionic bonds: HOT or NOT?
Totally Hot!
Definitely HOT Baby!