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Transcript of 1 + - + - + - BONDING 2 3 + - + - + - IONIC BONDING.
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+-BONDIN
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NIC
BONDIN
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IONIC RADII
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Zeff
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MONOATOMIC CATIONS
LOW IONIZATION ENERGY ELEMENTSELECTROPOSTIVE ELEMENTS LOSE SOME OR ALL OF THEIR VALENCE ELECTRONS
LOSE HIGHEST n QUANTUM NUMBER FIRSTTRANSITION ELEMENTS: HIGHEST ns FIRST; THEN d
Na: [Ne]3s1 Na1+: [Ne]Ca: [Ar]4s2 Ca2+: [Ar]
Fe: [Ar]3d64s2 Fe2+ : [Ar]3d6
Fe3+ : [Ar]3d5
LOSE HIGHEST SUBLEVEL (l) FIRST
Sn: [Kr]4d105s25p2 Sn2+: [Kr]4d105s2
Sn4+: [Kr]4d10
REMINDER: CATION RADIUS < ATOM RADIUS
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MONOATOMIC ANIONS
ELECTRONEGATIVE ELEMENTS GAIN ELECTRONS
NUMBER GAINED IS AMOUNT NEEDED TO FILL VALENCE ORBITALS ....HIGHEST p SUBLEVEL
O: [He]2s22p4 O2-: [He]2s22p6 O2-: [Ne]
I: [Kr]4d105s25p5 I1- : [Kr]4d105s25p6 I1- : [Xe]
REMINDER: ANION RADIUS > ATOM RADIUS
TO HELP REMEMBER MONOATOMIC ANION CHARGE:
GROUP NUMBER - EIGHT …….OR
EIGHTEEN - GROUP NUMBER
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IONIC COMPOUNDS
ELECTROPOSITIVE ELEMENT TRANSFERS OR LOSES ELECTRON(S) TO THE ELECTRONEGATIVE ELEMENT
METAL LOSES ELECTRON(S) TO NON-METAL
NaF CaF2 FeF3
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COVALENT BONDS
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IONIC BONDS:
TRANSFER ELECTRONS FROM HIGHER E ORBITALS TO LOWER E ORBITALS
USUALLY: METAL + NON-METAL
NOT INDIVIDUAL MOLECULES
SPHERICAL, NON-DIRECTIONAL CHARGE
NaCl MgF2 BaO
COVALENTBONDS
SHARING OF ELECTRONS
USUALLY: BETWEEN NON-METALS
DIRECTIONAL BONDS
INDIVIDUAL MOLECULES
CO CO2 C2H5OH
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POLAR COVALENT BONDS
ELECTRONEGATIVITY (): MEASURE OF ATOM’S ABILITY TOATTRACT BONDING ELECTRONS
NON-POLAR COVALENT BOND: = 0 H2, Cl2, O2
POLAR COVALENT BOND: > 0 HCl, H2O, ICl
H Cl
= 2.1 3.0 = 0.9
BOND DIPOLE
BOND POLARITY INCREASESAS INCREASES
ROUGH RULE: > 1.8, BOND IS CLASSIFIED AS IONIC
METAL + NON-METAL = IONICNON-METAL + NON-METAL = COVALENT
. ...
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IN EACH OF THE FOLLOWING, IDENTIFY THE MORE POLARBOND AND INDICATE THE DIRECTION OF THE DIPOLE.
P-F OR S-F
N-F OR P-F
C-H OR O-H
Al-Cl OR Si-Cl
REMEMBER: INCREASES UP A GROUPAND ACROSS THE PERIOD
S > P
P-F > S-F
P-F IS MORE POLARDIPOLE TOWARDS F
N > P P-F IS MORE POLARDIPOLE TOWARDS F
O > C O-H MORE POLARDIPOLE TOWARDS O
Si > Al Al-Cl MORE POLARDIPOLE TOWARDS Cl
IONIC
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LEWISSYMBOLS:
PICTORIAL REPRESENTATIONS OF VALENCE SHELL ELECTRONS
SHOWS OUTERMOST ELECTRONS IN4 “ORBITALS” FOLLOWING HUND’S RULE
C
H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
OCTET
DUET
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FF F FF FFF
BONDING PAIRNONBONDING PAIRS(LONE PAIRS)
TO DETERMINE LEWIS STRUCTURES, YOU NEED:
ELECTRONS REQUIRED:ER = 8 x NON-H ATOMS + 2 x H ATOMS
VALENCE ELECTRONS AVAILABLEVE = (VALENCE ELECTRONS IN ALL ATOMS)
SHARED PAIRS (NUMBER OF BONDS) SP = ½ (ER-VE)
LONE PAIRS = ½ (VE) - SP
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GUIDES FOR DETERMINING LEWIS STRUCTURES OF SYSTEMS OBEYING THE OCTET (DUET) RULE
DETERMINE ER, VE, SP, & LP
DRAW MOLECULE WITH SINGLE BONDS
UNLESS NOTED: FIRST ATOM IS CENTRAL
ADD OTHER BONDS TO SATISFY SP
ADD LONE PAIRS TO SATISFY OCTET(S)
ON MOST ELECTRONEGATIVE ATOMS FIRST
WORTH NOTING:
H ATOMS CAN ONLY HAVE 1 BOND (TERMINAL ATOMS)
HALOGENS: 1 BOND UNLESS CENTRAL ATOM
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DRAW LEWIS STRUCTURES FOR:
CH4
H2O
ER =
VE =
SP =
ER =
VE =
SP =
LP =
LP =
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DRAW LEWIS STRUCTURES FOR:
F2
HCl
ER =
VE =
SP =
ER =
VE =
SP =
LP =
LP =
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DRAW LEWIS STRUCTURES FOR:
PF3
NH3
ER =
VE =
SP =
F P F
F
ER =
VE =
SP =
LP =
LP =
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WHAT IS THE LEWIS STRUCTURE OF O2?
ER = 8 x # O ATOMS16 ELECTRONS NEEDED
VE = 2 O ATOMS x 6 e- PER ATOM12 ELECTRONS AVAILABLE
SP = ½(ER-VE) = ½ (16-12)
2 SHARED PAIRS 2 BONDS
O O
WHAT IS THE LEWIS STRUCTURE OF C2H2?
ER = 2 x 8 e- + 2 x 2 e- 20 e-
VE = 2 C ATOMS x 4 e- + 2 H ATOMS x 1 e-10e-
SP = 1/2 (20 e- - 10e-)
5 SHARED PAIRSH C C H
LONE PAIRS = ½ (VE) - SP = ½ (12) - 2 =4
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BOND ORDER: NUMBER OF SHARED ELECTRON PAIRSC C
C C
C C
BO = 1 OR SINGLE BONDBO = 2 OR DOUBLE BOND
BO = 3 OR TRIPLE BOND
BOND STRENGTH OF A SPECIFIC BOND INCREASES AND BOND LENGTH DECREASES AS BOND ORDER INCREASES
CO C O C O
CO C O C O
STRENGTH
LENGTH
< <
> >
358 799 1058 kJ/MOLE
1.43 1.23 1.13 Ao
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MOLECULARSTRUCTURE
VSEPR
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VALENCE SHELL ELECTRON PAIR REPULSION
VS E P RELECTRON REGIONS OR GROUPS OF NEGATIVE CHARGE
AROUND AN ATOM REPEL ON ANOTHERATTAIN POSITION TO MINIMIZE REPULSION
1 ELECTRON GROUP OR ELECTRON REGION IS A:
LONE PAIR
SINGLE BOND
DOUBLE BOND
TRIPLE BOND
THE MOLECULAR SHAPE IS DETERMINED USING THESE ELECTRON GROUPS
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What does it mean to hybridize?
• Hybridization is the “chemistry word” for promoting electrons to an empty orbital
3 6 2 6
2 4 5 3
1 7 1 7
5 8 4 8
The #2 “s” electron becomes a “p” and #5 “p” becomes a “s”!
Hybridization Summary Table
Geometry HybridizationTotal e-
pairsShared pairs
Lone pairs
Angle Sketch
Linear sp 2 2 0
Trigonal Planar
sp2 3 3 0
Bent sp2 3 2 1
Linear sp2 3 1 2
Tetrahedral sp3 4 4 0
Trigonal Pyramidal
sp3
4 3 1
Bent Angularsp3
4 2 2
Linearsp3
4 1 3
Hybridization Summary Table
Geometry HybridizationTotal e-
pairsShared pairs
Lone pairs
Angles Sketch
Trigonal bipyramidal
sp3d 5 5 0
See-Saw sp3d 5 4 1
T-shaped sp3d 5 3 2
Linear sp3d 5 2 3
Linear sp3d 5 1 4
Hybridization Summary Table
Geometry HybridizationTotal e-
pairsShared pairs
Lone pairs
Angles Sketch
ocatahedralsp3d2
6 6 0
Square pyramidal
sp3d2
6 5 1
Square planar
sp3d2
6 4 2
T-shapedsp3d2
6 3 3
Linearsp3d2
6 2 4
Linearsp3d2
6 1 5
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OBEY OCTET RULE: 2, 3, OR 4 ELECTRON GROUPS
180 o
120 o
109 o
THE “MOLECULAR SHAPE” ANALYSIS INCLUDES:
DETERMINE NUMBER OF ELECTRON GROUPS
DETERMINE APPLICABLE SHAPE
NAME THE SHAPE
LINEARTRIGONAL
PLANER TETRAHEDRAL
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WHAT IS THE SHAPE OF THE FOLLOWING:
PF3
CH4
O3
F P F
F
TRIGONAL PYRAMIDAL~109 o BOND ANGLE
P
FF F
H
H C H
H
TETRAHEDRAL109 o BOND ANGLEC
HH
H
H
O O OBENT
~120 o BOND ANGLE
O
O O
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MORE THAN 4 ELECTRON REGIONS?
5 = TRIGONAL BIPYRAMIDAL
6 = OCTAHEDRAL
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LARGE MOLECULES? DIFFERENT REGIONS!
CAEFFINE
LINEAR
TETRAHEDRAL
TRIGONAL PLANAR
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BOND ORDER (AGAIN)!
FF
ELECTRON DENSITY
INTERNUCLEAR AXIS BONDNODAL PLANE
BOND
EVERY BOND CONTAINS 1 BONDMULTIPLE BONDS CONTAIN 1 BOND + BONDS
FF SINGLE BOND = BOND
O ODOUBLE BOND = BOND + 1 BOND
H C C H TRIPLE BOND = BOND + 2 BONDS
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HYBRIDIZATION RULESONLY FORM IN MOLECULES; NOT ATOMS
COVALENTLY BONDED POLYATOMIC MOLECULESONLY MIX NON-DEGENERATE ORBITALSsp, spd BUT NOT ss OR ppREQUIRES ENERGY INPUT
O
O H
H C O
H C O H
H O C H
H C O C
H
sp3
4 BONDS
sp2
1 C-C1 C-H1 C-OOTHER pORBITAL ISIN BOND
3
C-O
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VALENCE BOND THEORY LOCALIZES BONDING ELECTRONSDIFFICULT TO EXPLAIN RESONANCE
MOLECULAR ORBITAL THEORY DELOCALIZES ELECTRONS
C C
FREEDOM TO MOVEFREEDOM TO SPREAD
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C BONDIN
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Metallic Bonding• With atoms of the same metallic element
• Delocalized electron clouds caused by metallic atoms being so physically close to each other
• Known as a “sea of electrons”
• Reason why metals are such good conductors
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