Word
Electronegativity
Electronegativity difference
Bond
Definition
The ability of an atom to gain or keep electrons
The difference in electronegativity between two elements in a bond.
Valence Electrons
A connection between two or more atoms that results in new chemical properties
An atom’s outer layer of electrons
Octet Rule
Stable Octet
Atoms are most stable with 8 valence electrons. Exceptions: Hydrogen and Helium.
Eight valence electrons
Covalent Bond
Polar covalent bond
A chemical bond formed when two nonmetal atoms share valence electrons
A chemical bond formed when two nonmetal atoms share valence electrons unequally .
Nonpolar covalent bond A chemical bond formed when two atoms share valence electrons equally
Ionic Bond
Metallic Bond
Dispersion forces
A chemical bond formed when electrons are transferred from one atom to another, turning both into ions.
A bond where all electrons are shared between all nuclei of a metal .
Often described as “a sea of mobile electrons”.
A weak force of attraction between nonpolar atoms or compounds. Also known as London or Van Der Waals forces.
Dipole-dipole forces An attraction between polar covalent molecules
Ionic compound
Binary compound
Polyatomic Ion
Anion
Cation
Molecule
Network solid
Polar molecule
Nonpolar molecule
Compounds consisting of a metal and a nonmetal .
A compound that consists of two elements
An ion formed by atoms bonding together in such a way that a net charge is formed.
A negatively charged ion.
A positively charged ion.
A particle made of nonmetal atoms covalently bonded together to form a distinct particle.
A large repeating pattern of covalently bonded nonmetal atoms with no distinct molecules.
A molecule with asymmetrical electron distribution resulting in partially charged ends. Also knows as a dipole.
A molecule with symmetrical electron distribution resulting in any polar bonds canceling each other out to yield no partially charged ends.
Hydrogen bonding A strong attractive force between polar molecules where one molecule contains H and the other molecule contains N, O or F. The H of one molecule attracts strongly (almost with ionic strength) to the N, O or F of the other molecule.
Intermolecular Forces Forces of attraction between particles

Bonding
*Atoms gain, lose, or share electrons to achieve a full outer valence layer and become more stable*
A. Elements join to form compounds with different chemical and physical properties
1. Dependent on elements involved (metal, nonmetal) and the type of bond formed (ionic, covalent, metallic)
B. Compounds contain elements chemically combined in a fixed proportion (ex: ammonia always contains a
1:3 ratio of nitrogen atoms to hydrogen atoms) and can only be broken apart by chemical means
C. Compounds have specific chemical formulas, and can be named according to IUPAC rules
D. Physical properties are dependent on chemical bonds and intermolecular forces. These properties include malleability, solubility, conductivity, hardness, melting point, and boiling point
E. There are three types of bonding
1. Ionic – electrons transferred (between a metal and a nonmetal) - note: ionic compounds which contain polyatomic ions will have both covalent and ionic bonding
2. Covalent (Nonmetals)– electrons shared
Two different nonmetals (ex: H-O) = Polar bond
The same nonmetals (ex: H-H) = Non-polar bond
3. Metallic (metals) – mobile “sea of valence electrons” shared by all atoms
G. Atoms can gain or lose electrons to become ions
1. An anion is an atom that has gained one or more electrons, thus obtaining a negative charge and a larger radius
2. A cation is an atom that has lost one or more electrons, thus obtaining a positive charge and a smaller radius
H. Lewis Electron Dot Diagrams can be used to represent ionic and covalent bonding by showing the arrangement of valance electrons
I. Atoms bond with one another to release energy, obtaining a stable valance electron configuration.
1. The noble gases with a full valance shell are already stable.
J. How strongly an atom attracts the electrons in a chemical bond is indicated by its electronegativity
1. Electronegativity is the ability of an atom to attract electrons to itself
K. The difference in electronegativity between two bonded atoms determines the degree of polarity of the bond.
1. The greater the electronegativity difference the greater the polarity of the bond
L. Molecular polarity can be determined by the shape of the molecule and the distribution of charge.
1. Symmetrical molecules are non-polar because electronegativity differences cancel each other out
2. Asymmetrical molecules are polar because of the difference in electronegativity values
M. There are three main types of intermolecular forces
1. Hydrogen bonding is created by the unequal distribution of charge between the hydrogen atom in one molecule with an extremely electronegative element in another molecule (N,O,F).
a) Strongest IMF  highest melting and boiling points
2. Dipole-Dipole forces are the attraction between oppositely charged ends of neighboring polar molecules
a) The greater the polarity the stronger the IMF
3. Dispersion forces (also called London, or Van Der Waals) are weak forces between nonpolar molecules
a) Weakest IMF  lowest melting and boiling points
N. The different types of bonding influence the properties of materials
1. Ionic Solid
Force of attraction is quite strong!
High melting point due to high temp. needed to overcome both inter- and intra- molecular bonds

Poor conductors of electricity - except in the liquid state when the ions are free to move around
2. Molecular Solid
Relatively soft, low melting point due to weak intermolecular forces that are easy to overcome.
Good insulators
Does not conduct electricity due to no free moving electrons
3. Metallic Crystals
Good conductors of electricity
Malleable and ductile – the attraction between the nuclei and electrons holds the metal crystal together
4. Covalent Network Solids
Very hard, high melting points, nonconductors of electricity.
Share e- but compressed so much that there is a network like diamond
Complex – very strong
O. Energy always plays a role in simple chemical reactions
1. Chemical changes result in the shift of energy a.) The formation of bonds is exothermic – energy is released (more stable) b.) The breaking of bonds is endothermic – energy is absorbed (less stable)
P. Energy, mass and charge are all conserved in every chemical reaction. “Laws of Conservation”
Caution: There is a difference between BOND Polarity (Classification) and MOLECULE polarity (Classification)
[name of Cation] [name of Anion] change ending to –ide
Note: Polyatomic ions keep their names as is. (see
Table E)
IONIC COVALENT
Does the cation have more than one possible oxidation state?
NO YES
Use prefixes (mono, di, tri, tetra) to indicate multiple atoms of the same element.
Note: No prefix is needed on the cation if there is only 1 of them. name is complete  name of the compound must include the oxidation state in
(roman numerals) immediately following the element.

1) IONIC BONDING HOMEWORK
1) Draw a dot diagram of an ion of potassium ionically bonding to an ion of chlorine, to make potassium chloride
(KCl).
2) Draw a dot diagram of an ion of calcium ionically bonding to two atoms of fluorine, to make calcium fluoride
(CaF
2
).
3) Draw a dot diagram of two ions of sodium ionically bonding to an ion of oxygen (oxide), to make sodium oxide
(Na
2
O).
4) Which species will conduct electricity (is an electrolyte)? a) NaCl (s) b) N
2
(s) c) LiF (aq) d) CaI2 (s)
5) Explain how you determined the answer to #4.
To conduct electricity free moving electrons or ions must be present. Only choice C, the soluble ionic compound in solution would have sufficient free flowing charged ions to conduct electricity
6) Which species will form an anion when forming an ionic bond? c) S d) Sr a) O b) Li
7) Explain your answer to #6.
Species A and C are nonmetals which will form negative ions or anions in an ionic bond.
8) Why will Al+3 and O-2 attract while Al+3 and Fe+2 repel?
Aluminum ion will attract to the oxide ion because oppositely charged species attract. Aluminum ion and iron ion will repel each other because like charges repel each other.
9) What is the charge of an element before it forms a bond? Why?
Neutral because elements have an equal number of protons and electrons.

Topic 2) Properties of Ionic Substances Homework
1) Which substance has a high melting point and conducts electricity when dissolved in water? a) Mg b) KBr c) CH
4
2) List one experiment that can determine whether a substance is ionic or not: d) SiO
2
You could test the electrical conductivity when the substance is a solid and a liquid.
3) What would the expected outcome of the experiment be if the substance was ionic?
The substance should not conduct electricity in the solid form but should conduct electricity in the liquid form
4) Complete the following chart:
Ion Formula Ion Name Ion Name Ion Formula
+1
+3
-1
-3
+1
+1
+3
+1
+
3-
-
2+
4+
3+
3+
2+
Topic 3) Ionic Names and Formulas Homework
Formula Name
NaCl
Na
2
O
Sodium chloride
Sodium oxide
H
2
SO
4
Fe
3
(PO
4
)
2
HBr
Sulfuric acid (Hydrogen sulfate)
Iron (II) phosphate
Hydrobromic acid (Hydrogen bromide)

CaSO
K
2
O
ZnSO
4
3
Calcium sulfate
Potassium oxide
Zinc sulfite
(NH
4
)
2
SO
4
Ammonium sulfate
HCH
3
COO Acetic acid (hydrogen acetate)
PbCl
2
Lead (II) chloride
CuSO
4
Fe
2
S
3
Copper (II) sulfate
Iron (III) sulfide
AgNO
2
Name
Silver Nitrite
Lead (IV) chloride
Potassium oxide
Sodium phosphate
Ammonium nitrate
Lead (IV) sulfide
Silver chloride
Zinc sulfate
Aluminum iodide
Magnesium hydroxide
Tin (II) acetate
Ammonium oxide
Formula
PbCl
K
2
O
Na
3
4
PO
4
NH
4
NO
3
PbS
AlI
3
2
AgCl
ZnSO
4
Mg(OH)
2
Sn(CH
3
COO)
2
(NH
4
)
2
O
Potassium permanganate KMnO
4
Iron (III) chloride
Sodium cyanide
FeCl
3
NaCN
Topic 4: Covalent Bonding Homework
1) Complete the following chart, drawing the dot diagram of each element in the molecule and then the dot diagram of the molecule. If the formula is H
2
O, make sure you have two atoms of H and one of O in your dot diagram of the molecule.
Formula Dot diagram for: Dot diagram for: Dot Diagram of Molecule
F F F
2
H Br HBr

H
2
O H O
NH
3
N H
2) Identify the following bonds as being polar covalent or nonpolar covalent. For the polar covalent bonds, label the + and ends.
Bond Polar or Nonpolar? If polar, label the + and - ends
Nonpolar H
– H
Polar + H
– C
-
Polar
Polar
Polar
Nonpolar
Polar
Polar
Nonpolar
+ H
– Cl
-
+ C
– Cl
-
+ P
– Cl
-
Cl
– Cl
+ H
– P
-
+ H
– O
-
O
– O
3) When two atoms of nitrogen bond, how many pairs of electrons will be shared between them? a) 1 b) 2 c) 3 d) 4
4) When two atoms of fluorine bond, how many electrons will be shared between them? a) 1 b) 2 c) 3 d) 4
5) When an atom of H and an atom of F bond together: a) The H will be partially positive, because it has higher electronegativity than F. b) The H will be partially negative, because it has higher electronegativity than F. c) The F will be partially positive, because it has higher electronegativity than H. d) The F will be partially negative, because it has higher electronegativity than H.
6) Which of the molecules listed below has the most polar bond between the bonded atoms, in terms of greatest
END?
a) HF b) HCl c) HBr d) HI

7) Explain, in terms of electronegativity difference, why Cl
2
contains nonpolar covalent bonds.
Chlorine, when bonded to itself, there is no electronegativity difference between the atoms. The electron density is equally shared between the two chlorines so no poles are formed.
8) Explain, in terms of electronegativity difference, why H
2
O contains polar covalent bonds.
When hydrogen is bonded to oxygen the electrons are not equally shared between the two atoms because oxygen is more electronegative. This difference in electronegativity causes a partial positive charge to develop on hydrogen and a partial negative to develop on oxygen.
Topic 5: Covalent Compounds Homework
1) For each of the following molecules represented by structural formulas indicate a) if the molecule is polar or nonpolar. b) If polar, label which side is partially positive and which side is partially negative. c) Identify the shape of the molecule d) identify the type of attractive force that will hold molecules of this substance together in the liquid and solid phase. e) Name the molecule
If nonpolar, b) and c) do not get done.
Molecule (do B here) Polar or Nonpolar Shape IMF Type Name
H – Cl Polar Linear
Dipoledipole forces
Hyrdogen chloride
(hydrochloric acid)
H – H Nonpolar Linear
Dispersion forces
Hydrogen
H – O
|
H
Polar Bent
Hydrogen bonding forces
Water
Dihydrogen monoxide
H - N – H
|
H
Polar Trigonal
Pyramidal
Hydrogen bonding forces
Nitrogen trihydride
Ammonia
Cl
|
Cl – C – Cl
|
Cl
Nonpolar Tetrahedral
Dispersion forces
Carbon tetrachloride
O = C = O Nonpolar Linear
Dispersion forces
Carbon dioxide
H – Br
Polar Linear Dipoledipole forces
Hydrogen bromide
(hydrobromic acid)

2) As a general rule, the boiling point of a molecular substance increases as the molecular mass increases.
Create a graph with molecular mass on the X axis and the boiling point on the Y axis. Start temperature at 100K and molecular mass at 0 grams/mole. Plot the data below:
Substance Molecular Mass (grams/mole) Boiling Point (K)
H2S
H2Se
34
81
211
229
H2Te 130 271 a) H2O has a molecular mass of 18 g/mol. Extrapolate the curve and estimate the boiling point of water, putting an X in a circle on the extrapolated line at 18 g/mol.
On graph b) Water actually boils at 373 K. Put an “A” where the actual boiling point of water is, at 18 g/mol, NOT on the extrapolated line.
On graph c) Is the actual boiling point of water higher or lower than the extrapolated estimate?
The actual boiling point is much higher than the extrapolated d) Explain why this difference exists in terms of the specific kind of attractive force that holds water molecules to each other in the solid and liquid phase.
Water molecules are held together by hydrogen bonding which is much stronger than the dipole-dipole forces that hold the substances on the graph. To boil a substance the intermolecular forces must be overcome, so stronger intermolecular forces take more energy to separate.
3) Identify the type of compound indicated in the table of properties below and explain how you arrived at that determination (these include metallic and ionic, from previous units):
Compound Melting
Point
Boiling
Point
Electrical
Conductivity (s)
Electrical
Conductivity (l)
A
B
1074 K
42 K
2556 K
88 K
No
No
Yes
No
C
D
303 K
3820 K
2676 K
5100 K
Yes
No
Yes
No
A___ Ionic solid ____________________________________
Why: Compound A is likely an ionic solid because it has a very high melting point, and conducts electricity as a liquid but not a solid.
B___ Molecular solid ____________________________________________
Why: Compound B is likely a molecular solid because it has a very low melting point and is a poor conductor of electricity in both the liquid and solid phase.
C___ Metallic solid ____________________________________________
Why: Compound C is likely a metallic solid because it is a great conductor of electricity.
D___ Covalent Network Solid ____________________________________________
Why: Compound D is likely a covalent network solid because it has an extremely high melting point and does not conduct electricity