bonding&m&ch.7 types&of&bonding i. holds&everything ... ·...
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Types of Bonding
I. ________________________________holds everything together!II. All bonding occurs because of ________________________III. Electronegativity difference and bond character
A. A ________________________________________________ between two atoms results
in a __________________________________________ when those two atoms form a bond. B. Ionic and covalent bonding are not distinct categories as __________________________ It’s just that one is more prevalent than the other. C. EN is not the only factor. Whether they are metals or nonmetals also matter.IV. Covalent Bonding (____________ bonding)� A. Bond that exists between ____________ B. Involves____________________________________ C. Includes: 1. Polar covalent -‐ ____________________________________________________________________________________________________________ a. hydrogen bonding: ____________________________________________________________________________________________________________________________________________________________ b. dipole-‐dipole: ________________________________________________________________________________________________ 2. Nonpolar Covalent -‐ _____________________________________________________________________________________________________V. Ionic Bonding
A. Bond that exists between________________________
B. Involves the ____________________________________from the____________________________________ C. Ionic solids have a ________________________structure.VI. Metallic Bonding A. Bonding that exists between____________ B. Electrons are____________________________________________________________ C. Electrons act like___________________________________________________________ 1. give rise to properties such as _______________________________________________ 2. the more ________________________ or ________________________, the more ________________________________________________ (this is very general -‐ not a rule)
Nature of Bonding
I. Covalent bond nature A. Two nuclei have multiple electrostatic forces acting within it. 1. ________________________________________________ 2. ________________________________________________ B. Attractive forces________________________ at an________________ ________________ 1. According to the graph, ________ is the optimal bond length.
Bonding -‐ Ch. 7
2. This is the ________________________________ where the _____________________________________________________ are balanced. C. ________________________ hold bond together.II. Ionic bond nature A. Metals have ______________________ and would more likely ______________________ to a nonmetal (which have_________________________________). B. Ionic structures are held together by ______________________ (___________________________________________________________________________). C. Ionic compound is more stable because all ions involved __________________________ D. Cations and anions in an ionic crystal are arranged in a lattice (______________________) that _________________________________ between ions while ____________________________________________.III. Properties: A. Ionic compounds are orderly (_______________) so they are _____________________________________________ B. Molecules don't usually form ordered structures so ____________________________________________________________IV. Bottom line: All elements want to bond because they form _____________________________________________V. More on this in later chapters...VI. One more thing... A. Ionic bond strength 1. ____________________________________________________________ 2. The ______________________________, the _______________ic attraction. 3. Predicted by Coulomb’s Law: a.
i. F=______________________________ ii. ke=______________________________ iii. q1 &q2 = ______________________________ iv. r= ______________________________ 4. Electrostatic attraction is... a. ______________________________ b. ___________________________________between charges. 5. The________________________________________________________________________________________________________________________
Bonding -‐ Ch. 7
Lewis Structures -‐ Covalent Bonding
I. All smaller atoms are more stable with ____________________________(______________) A. Except for ______________(______________) B. Some atoms with ____________________________can have______________ (__________________________________________).II. Lewis Structures show how molecules share electrons. A. A line represents a _______
B. Unshared/lone pair -‐ ____________________________
III. How to draw them: A. Count the total number of valence electrons B. Arrange the atoms (C is usu. middle. Also, element that is least abundant is in the middle). C. Draw single bonds between all atoms and subtract the number used from total (one line=2 electrons!) D. Place the rest of the electrons around outer elements until all of them have eight. 1. Extra electrons? Put them on the central atom.� 2. Need electrons? Move electrons from outer atoms to create double and triple bonds. E. Check work! 1. Does the number of electrons in structure equal the total number of valence electrons? 2. Does every element follow the octet rule?
IV. Resonance structures: molecules that have more than one possible Lewis structure. A. Shown through a double sided arrow: ↔ B. Actual structure is an ______________ (like an average) of all the resonance structures. C. Therefore, the __________________________________________ bonds present.
D. Bond order: 1. Single bond =___, double bond = ___, triple bond = ___ 2. Bond orders for resonance structures are an __________________________________ of all the bonds present. For example: For nitrate, the bond order is ___V. Ions: Don't forget to place ______________around ions and to __________________________________________________VI. Exceptions to Octet Rule A. Some are ____________________________:______________ B. Some can be __________________________: P, S, Cl, As, Se, Br, Kr, Sb, Te, I, Xe (p. 171) 1. Because________________________________________________________ 2. Place any extra electrons on the central atom of these even if it already has eight!
Bonding -‐ Ch. 7
VII. Acidic and basic Lewis structures: __________________________________________VIII. A more thorough method of checking your structure: ____________________________ A. Molecules will be arranged in the structure in which ______________________________________________________________________________________ B. Formal charge = __________________________________________ C. Calculate formal charge for each atom in structure! D. This explains the octet rule exceptions (Ex. BeF2).
VSEPR
I. VSEPR states that ____________________________ A. Electrons will orient themselves ____________________________ B. Lone pairs, since they are ________________________________________, will ________________________________________________________ C. This is used to predict ____________________________ (Think in 3-‐D!!!)II. Refer to the table summarizing the shapes. A. Angular means bent.
Polarity
I. Electronegativity (Table 6.5 on p. 154): __________________________________________. A. Used to determine ____________________________ B. If difference is... 1. >2.0 = ionic 2. 0.5<x<1.6 = polar covalent 3. 0.5> = nonpolar covalent 4. For ______________, the bond is ____________________________. The bond is __________________________________________ C. The trend in type of bond is the same as the trend regarding _______________________ ____________________________II. Dipole: Molecule that has ____________________________ (__) on one end and a __________________________________________(__) on the other.III. Dipole moment shows ____________________________( ____)IV. How to determine polarity: A. If all dipole moments (polar bonds) ____________________________ If they do not cancel out, the molecule is__________________________________________ B. Generally,__________________________________________. DO NOT explain using only the symmetry argument!
Bonding -‐ Ch. 7
Orbital Hybridization
I. The shapes we know don't match shapes from Ch. 6!!! A. As elements form a bond, their orbitals become a ________________________________________________________ B. You can determine ________________________________________________________ 1. Look at table again...hybridization = _______________________________________________________________________________ 2. Ex: NH3 = 1 lone pair & 3 atoms=4 orbitals. Thus, it is _______ hybridized.II. Multiple Bonds (memorize) A. A single bond is known as a ________(___) bond.
B. A double bond contains __________ (___) bond and ________ (___) bond (________________________________________). C. A triple bond contains ________________ (___) bond and ________ (___) bonds. D. π bond is ________________ σ bond. E. Also, π bonds ___________________________ and leads to ________________________ (more about this in O chem) F. If many ______________________ π bonds are present, molecules may conduct electricity. G. Examples...
Other Theories
I. As with atomic theory, bond theories/models have gone through many revisions. A. Valence Bond Theory vs. Molecular Orbital Theory B. Lewis Structures, Ball and Stick Model, Space-‐Filling ModelII. Though they have all proved beneficial, all theories and models have limitations.
Bonding -‐ Ch. 7