Chapter 8 Chemical Bonding Study Guide

Define Oxidation Number

Combining capacity (How many bonds) Group 14 - Holds 4 bonds Group 15- Holds 3 bonds Group 16- Holds 2 bonds Group 17- Holds 1 bond

Describe a diatomic element.

Combining two of the same elements to form a molecule ex. F2, and Cl2

Naming Molecules

End in oxide if oxygen is present, or ide if not, and do not use mono in the first element

What occurs when a bond breaks?

Energy is Absorbed

What occurs when a bond forms?

Energy is released

What element is the electronegativity scale based on and what is its assigned value?

Florine and 4.0 paulings

List the diatomic elements.

Hydrogen, Bromine, Iodine, Oxygen, Nitrogen, Florine, and Chlorine. HONClBrIF

Explain an Exothermic Reaction. Include Graph.

It occurs when a greater amount of energy is released during bond formation in the products than is required to break bonds in the reactants. Container feels hot because Energy is Released

Explain an Endothermic Reaction. Include Graph.

It occurs when a greater amount of energy is required to break the bonds in the reactants than the energy release to form bonds in the products Container feels Cooler because it is absorbing energy

Do metals have high or low electronegativities? What does this mean?

Metals have low electronegativity and they loose electrons more readily

Do nonmetals have high or low electronegativities? What does this mean?

Non-Metals have high electronegativity and they tend to gain electrons more readily

Who devised the electronegativity scale?

Pauling

Define bond-disassociation energy.

The amount of energy required to break a specific covalent bond (Always Positive)

Define Electronegativity.

The attraction an atom has for its electrons, in its sharing with another atom

What does the difference in electronegativities of two elements less than 2 mean?

The bond is Covalent

What does the difference in electronegatavites of two elements greater than 2 mean?

The bond is Ionic

What does the difference in electronegativities of two elements equal to 2 mean?

The bond is Ionic

How can you tell whether two elements bond ionically of covalently?

The difference in their electronegativity ( subtract bigger from smaller) Less then 2 is ionic, Greater then or equal to 2 is covalent

Define Bondlength

The distance between the two bonded nuclei of atoms

Define Nonpolar Bond

The equal sharing of electrons (Diatomic Elements)

Define Polar Covalent Bond

The kind of covalent bond in which there is unequal sharing of electrons

Relate the length of a bond with the strength of the bond: a) Single Bond b) Double Bond c) Triple Bond

The shorter the bond length, the stronger the bond Single Bond: Very long and Very weak Double Bond: Medium Strength and Medium Length Triple Bond: Very Strong and Very Short

Why do diatomic elements exist?

They exist to form stable octet and hydrogen forms a stable duet

Write electron dot structure for the following elements (atoms) a) Li b) Be c) B d) C e) N f) O g) F h) Kr i) Rb j) Sb k) I l) Ba m)Cl

They represent the arrangement of electrons in a molecule Groups 1(1 Valence Electron)-2, 13-18 (8 Valence Electrons)

Determine the ionic percentage and covalent percentage of each bond in the following compounds: a)CH4 b) M2 c) FeO d) NH3 e) SO2 f) HCl g) NaF

a) 2.5-2.1= 0.4 4.0 % Ionic ; 96.0 % Covalent b) 3-3=0 0% Ionic ; 100 % Covalent c) 3.5-1.9=1.7 51% Ionic; 49 % Covalent d) 3.0-2.1=0.9 19% Ionic; 81% Covalent e) 3.5-2.5= 1.0 22% Ionic; 78% Covalent f) 3.0-2.1=0.9 19% Ionic; 81 % Covalent g) 4-0.9= 3.1 91% Ionic; 9% Covalent

Determine wheter the bonds in the following compounds are ionic or covalent: a) H2 e) KCl i)OF2 b) MgO f) NH3 c) KCl g) C2F2 d) H2S h) HBr

a) H2~2.1-2.1=0~Covalent b) N2~3-3=0~ Covalent c)MgO~3.5-1.2=2.3 Ionic d) H2S~ 2.5-2.1=0.4 Covalent (only use 2 elements) e) KCl~3.0-0.8=2.2~ Ionic f) NH3~ 3.0-2.1=0.9 Covalent g) CaF2~4-1=3 Ionic h) HBr~2.8-2.1=0.7 Covalent i) OF2~ 4.0-3.5=0.5 Covalent

Name each molecule: a) NF3 b) NO c) SO3 d) SiF4 e) SeO2 f) SeO3 g) NaF4 h) S4N4 i) PCl3 j) Cl2O2 k) P4O6 l) SiI4

a) Nitrogen Triflouride b) Nitrogen Monoxide c) Sulfur Trioxide d) Silicon Tetraflouride e) Selenium Dioxide f) Selenium Trioxide g) Sodium Tetraflouride h) Tetrasulfur Tetranitride i) Phosphorus Trichloride j) Diclorine Dioxide k) Tetraphosphorus Hexaoxide l) Silicon Tetraiode

Determine whether the bonds in each of the following molecules are polar or nonpolar. Determine whether the molecule itself is polar or nonpolar. a) H2 b) O2 c) HCl d) H2O e) CH4 f) N2 g) HBr h) CCl4 i) F2 J) CHCl3

a) Nonpolar bond bond and molecule b) Nonpolar bond and molecule c) Polar bond and molecule d) Polar bond and molecule e)Polar bond and Nonpolar molecule f) Nonpolar bond and Molecule g) Polar bond and molecule h) Polar bond and Nonpolar molecule i) Nonpolar bond and Molecule j) Polar Bond and Molecule m) Polar bond and Molecule n) Polar bond and Molecule o) Polar bond and Nonpolar Molecule

Write the Formula for Each Molecule: a) Sulfur Diflouride b) Silicon Tetrachloride c) Carbon Tetraflouride d) Silicon Dioxide e) Chlorine Triflouride f) Hydrobromic Acid g) Chlorine Monoxide h) Phosphorus Pentachloride i) Hydrosulfuric Acid

a) SF2 b) SiCl4 c) CF4 d) SiO2 e) ClF3 f) HBr g) ClO h) PCl5 i) HS