L3 Chemical Bond September2014
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Transcript of L3 Chemical Bond September2014
CHEMICAL BOND &
MOLECULAR GEOMETRY
Naming of compounds
Types of bonding
• Ions: cations, anions, oxoanions• Ionic compounds• Covalent compounds: 4 rules
• Ionic bond: transfer of electron(s)• Covalent bond: sharing of electron(s)
Types of compounds• Ionic compounds: metals + nonmetals• Covalent compounds: between metals
SUMMARY OF LAST WEEK
Quantum numbers: n, l, ml and ms
n: determines the energy of the “orbital”
l: determines the shape of the orbital ( l= 0, 1,…..n-1); l= 0 is “s”, l=1 is “p”, l=2 is “d” etc
m (or ml): determines the orientation of the “orbital”; m= -l,…,0,…,+l;therefore: 1s orbital, 3p orbital, 5d orbital
ms: describes the spin of the electron, m= +1/2, -1/2
SUMMARY OF LAST WEEK
SUMMARY OF LAST WEEK
Multi-electron configuration:
Pauli Exclusion Principle: no 2 electrons in an atom may be in the same quantum state (n,l,ml,ms)
Aufbau Principle: electrons adopt the lowest possible energy
Shielding: orbitals of equal n nearest the nucleus have lowest energy
Hund’s Rule: in orbitals, electrons prefer to be unpaired first
SUMMARY OF LAST WEEK
PART 1: CHEMICAL BOND
Highlight:
• Covalent bond
• Ionic bond
• Metallic bond
THIS WEEK
CONCEPTS Valence electron Lewis dot formula Electronegativity Polar, non polar bond Polarity Dipole, dipole moment
Highlight:
• Lewis structure
• Octet rule
• Molecular
geometry
THIS WEEK
PART 2: MOLECULAR SHAPE
CONCEPTS How to draw a LEWIS structure Octet rule VSEPR (Valence-Shell Electron Pair Repulsion) theory Determine the molecular shape by VSEPR
PART 1: CHEMICAL BOND
THIS WEEK
CONCEPTSHighlight:
• Covalent bond
• Ionic bond
• Metallic bond
Valence electron Lewis dot formula Electronegativity Polar, non polar bond Polarity Dipole, dipole moment
CuSO4.5H2
O
NaCl
NiCl2.6H2
OK2Cr2O
7
CoCl2.6H2
O
IONIC COMPOUNDS
H2 O(water)
CO2
(carbon dioxide)
CH4
(methane)
C2H5OH(ethyl
alcohol)
COVALENT COMPOUNDS
Light bulb experiment
Why are the properties of a substance different from another ?
• Properties of an atom depend on the electron configuration and the strength of the nucleus-electron attractions
Similarly,
• Properties of a substance depend on the type and strength of chemical bonds
CHEMICAL BONDS the forces that hold the atoms of elements
together in compounds
CHEMICAL BONDS the forces that hold the atoms of elements
together in compounds
Highlight:
• Ionic bond: metals and nonmetals
• Covalent bond: nonmetals and
nonmetals
• Metallic bond: metal with metal
3 types of bondings
To understand bonding, we should know:
• Valence electrons• How to draw Lewis formula• Octet rule
Does electron configuration has any effect on chemical bond?
YES. But only the electrons at outer most shell will determine bonding
Numbers and arrangements of valence electrons determine:• chemical and physical properties of elements• kinds of chemical bonds
They are called valence electrons
Numbers and arrangements of valence electrons determine:• chemical and physical properties of elements• kinds of chemical bonds
Electron configuration:
Valence electrons: the outer most electrons of atoms11Na: 1s2 2s2 2p6 3s1
8O: 1s2 2s2
2p4
valence electrons: 1valence electrons: 6
Electron configuration:
Valence electrons: the outer most electrons of atoms11Na: 1s2 2s2 2p6 3s1
8O: 1s2 2s2
2p4
valence electrons: 1valence electrons: 6
Numbers and arrangements of valence electrons determine:• chemical and physical properties of elements• kinds of chemical bonds
Lewis formulas (Lewis dot formulas): to describe the valence electrons
11Na: 1s2 2s2 2p6 3s1
8O: 1s2 2s2
2p4
valence electron: 1
valence electrons: 6
Na
O•
•
••••
•
Only valence electrons of s and p orbitals: shown in dots
Number of valence electrons of GROUP A = group number
-Use Lewis symbol to express valence electrons
-It’s easy to write the Lewis symbol for any main-group element:
1. Note its A-group number (1A to 8A), which equals the number of valence electrons.
2. Place one dot at a time on the four sides (top, right, bottom, left) of the element symbol.
3. Keep adding dots, pairing the dots until all are used up.
Now, can you quickly write the Lewis symbol of all elements in group 6A?
The Lewis symbol provides information about an element’s bonding behavior:
• For a metal, the total number of dots = the maximum number of electrons an atom loses to form a cation.
Na• Al •••
Ca••
The Lewis symbol provides information about an element’s bonding behavior:
• For a nonmetal, the number of unpaired dots equals
either the number of electrons an atom gains in becoming an anion
or the number it shares in forming covalent bonds.
O••
••••
3 types of bonding: a closer look
IONIC BONDING
•Ionic bonding: forms between atoms with LARGE differences in their tendencies to lose or gain electrons.
•These differences results in transfer of electron from one atom to another in large numbers to form a compound.
IONIC BONDING
Normally, ionic bonding forms between reactive metals and nonmetals
Reactive metals:
Group 1A&
Group 2A
NometalsGroup 7A
&the top of group 6A
+low ionisation energy easily loses e-
very negative affinity easily attract e-
•The electrostatic attraction of the ions draw them into a 3D array of an ionic solid
The strength of ionic bonds depends on: Charges & Sizes
Proportional to
Coulomb’s Law:
q: Charge(s) of the ion(s)d: Distance between ions
STRENGTH OF IONIC BOND
Ions with higher charges and smaller sizes will attract each other stronger
Higher charges q +, q - increase F increases
Smaller sizes D decreases F increases
COVALENT BONDING
• Covanlent bonding: forms between atoms with small differences in their tendencies to lose or gain electrons.
COVALENT BONDING
• Normally, covalent bonding forms between nonmetals.
• Each nonmetal has HIGH ionisation energy: hold onto its own electrons tightly
HIGHLY negative electron affinity: attract electrons from others
• The attraction of each nucleus & valence electron: draw atoms close to each other
METALLIC BONDING
•Metals: can easily loose electron at outer shell• Electron pool• Electrostatic attraction
3 types of bonding
Ionic bonding
Covalent bonding
Metallic bonding
MODELS OF BONDING
Model of ionic bonding
Model of covalent bonding
3 types of bonding
Ionic bonding
Covalent bonding
Metallic bonding
MODELS OF BONDING
Model of ionic bonding
Model of covalent bonding
COVALENT BONDING
Why does covalent bonding form?
Key concepts
• Covalent bonding
• Shared and unshared pair
• Bond energy and bond length
• Bond polarity
• Dipole moment
COVALENT BONDING of H2
COVALENT BONDING
the atoms are too far apart to attract each other.
each nucleus attractsthe other atom’s electron.
The combination of nucleus-electron attractions and electron-electron and nucleus repulsions gives the minimum energy of the system.
repulsions increase the system’s energy and force the atoms apart to point 3 again.
COVALENT BONDING
Distribution of electron density
Covalent bonding : results from sharing one or more pair electrons between atoms
Covalent bonding occurs when the electronegativity difference, (∆EN), between elements (atoms) is zero or relatively small.
When can a covalent bond be formed?
Valence electron(s): participate in covalent bonding
COVALENT BONDING
• Shared or bond pair (electron pairs)• Unshared or lone pair
SHARED SHARED
Unshared Unshared
BOND PAIR & LONE PAIR
• Shared or bond pair (electron pairs)• Unshared or lone pair
SHARED SHAREDUnshared Unshared
BOND PAIR & LONE PAIR
• Bonding pair (electron pair): Bonding pair A pair of electrons involved in a covalent bond.Also called shared pair.
• Lone pair: A pair of electrons residing on one atom and not shared by other atoms; unshared pair.
BOND PAIR & LONE PAIR
H• H•+ H • •H
H-Hor
H• +
H-For
F•••
•••• H •F•
••
••••
FORMATION OF COVALENT BOND
Covalent bonding : results from sharing one or more pair electrons between atoms
Single covalent bond: two atoms share one electron pair. SINGLE BOND
Double covalent bond: two atoms share two electron pairs. DOUBLE BOND
Triple covalent bond: two atoms share three electron pairs. TRIPLE BOND
BOND TYPES
BOND ENERGY AND BOND LENGTH
•The strength of a covalent bond depends on the magnitude of the mutual attraction between bonded nuclei and shared electrons.
•The bond energy (BE) (also called bond enthalpy or bond strength) is the energy required to overcome this attraction.
BOND ENERGY AND BOND LENGTH
BOND ENERGY AND BOND LENGTH
• Bond energies depend on characteristics of the bonded atoms
their electron configurations, nuclear charges atomic radii
• A covalent bond has a bond length, the distance between the nuclei of two bonded atoms.
Bond Energy and Bond LengthEnergy: (kJ) average bond energyLength: (pm) average bond length
BOND LENGTH AND ATOMIC RADIUS
Energy: (kJ) average bond energyLength: (pm) average bond lengthWithin a series of similar molecules, such as the diatomic halogen molecules, bond length increases as covalent radius increases
BOND STRENGTH, LENGTH AND BOND TYPE
Between single bond, double bond and triple bond
• Bond length: single bond > double bond > triple bond
• Bond strength: single bond < double bond < triple bond
BOND STRENGTH, LENGTH AND BOND TYPE
Remember: the longer the length the lower the bond energies the lower the bond STRENGTH
Another example:
Trend atomic size: I > Br > ClLets compare: C-I > C-Br> C-Cl
How the Model Explains the Properties of Covalent Substances
• Most covalent substances have low electrical conductivity because electrons are localized and ions are absent.
• The covalent bonding model proposes that electron sharing between pairs of atoms leads to strong, localized bonds, usually within individual molecules.
How the Model Explains the Properties of Covalent Substances
• Most covalent substances have low electrical conductivity because electrons are localized and ions are absent.
• The covalent bonding model proposes that electron sharing between pairs of atoms leads to strong, localized bonds, usually within individual molecules.
Pentane
How the Model Explains the Properties of Covalent Substances
• Substances that consist of separate molecules are generally soft and low melting because of the weak forces between molecules.
• Solids held together by covalent bonds extending throughout the sample are extremely hard and high melting.
COVALENT BONDING
Key concepts
Covalent bonding
Shared and unshared pair
Bond energy and bond length
Electronegativity
Bond polarity
Dipole moment
BONDING
The ionic and covalent bonding models portray compounds as being formed by either complete electron transfer or complete electron sharing.
Questions: are all ionic bonds are 0% covalent?YESQuestions: are all covalent bonds are 0% ionic?Let’s learn about electronegativity?
One of the most important concepts in chemical bonding is electronegativity (EN).
(EN), the relative ability of a bonded atom to attract the shared electrons.
ELECTRONEGATIVITY
Electronegativity different from electron affinity (EA), • Electronegativity refers to a bonded
atom attracting the shared electron pair; • Electron affinity refers to a separate
atom in the gas phase gaining an electron to form a gaseous anion.
ELECTRONEGATIVITY
•There are also trends in electronegativity in the periodic table
• Electronegativity is inversely related to atomic size.
Atomic size decreases nucleus of a bonded atom attract more SHARED electrons electronegativity increases
•For the main-group elements, electronegativity generally increases up a group and across a period.
ELECTRONEGATIVITY
Questions: are all covalent bonds are 0% ionic?YES in NONPOLAR BONDNO in POLAR BOND
Because:Difference in ELECTRONEGATIVITY affect an electrostatic (charge) contribution
POLAR AND NONPOLAR COVALENT BONDS
Let’s have a look at:
H-H and H-F
POLAR COVALENT BOND:The electron pair is shared unequally
NONPOLAR COVALENT BOND:
H-H or H : H• Both H atoms have the same electronegativity electrons spend equal amount of time near each H nucleausthe electron density is SYMETRICAL The electron pair is shared equally • this covalent bond is NONPOLAR
The covalent bonds in ALL homonuclear diatomic molecules must be nonpolar.
H2, O2, N2, F2 and Cl2
Now consider heteronuclear diatomic molecules: HF
H-F or H : F
• H and F are two different atoms different electronegativity uneven electron density polar
• The electron pair is shared unequally• Asymetric electron density
POLAR COVALENT BOND
POLAR AND NONPOLAR COVALENT BONDS
Different distribution of electron density
Partial positive charge
Partial negative charge
one way to indicate polarity
Another way to indicate polarity
POLARITY: indicate how polar a compound is
Compare POLARITY?Which on is more polar?
HF HCl HBr HI
The higher the difference in EN the more polar a compound the higher polarity
• The separation of charge in a polar covalent bond creates an electric dipole.
We can express bond polarities on a numerical scale as dipole moment
DIPOLE MOMENT µ
d: distance of separationq: charge
DIPOLE MOMENT
Different distribution of electron density
DIPOLE MOMENT
What happened if we put a polar compound in an electric field?
FIELD OFF FIELD ON
So WE understood:
• Covalent bonding : polar and nonpolar
bond
• Electronegativity: is the attraction of
electron more toward a bonded atom
• Difference in EN causes a bond polar
• Polarity can be expressed in number by a
value called DIPOLE MOMENT
Question: is the polarity of a bond the same as a molecule containing that bond?
• Dipole moments only associated with individual bonds
The polarity of the entire molecules depends on MOLECULAR SHAPE (GEOMETRY) next part
COVALENT BONDING
SUMMARY
Key concepts
• Covalent bonding
• Shared and unshared pair
• Bond energy and bond length
• Bond polarity
• Dipole moment
Highlight:
• Lewis structure
• Octet rule
• Molecular
geometry
THIS WEEK
PART 2: MOLECULAR SHAPE
CONCEPTS Octet rule How to draw a LEWIS structure VSEPR (Valence-Shell Electron Pair Repulsion) theory Determine the molecular shape by VSEPR
MOLECULAR SHAPE (GEOMETRY)
We will know to explain the geometries of the molecules in term of their electronic structures.
Molecular geometry: • the general shape of a molecules• determined by relative positions of the atomic nuclei
To see what a molecule look like:• Know the molecular formula• 2D structure with Lewis dot formula:
the position of bonding pair, the position of lone pair central atom
should know the OCTET RULE
LEWIS FORMULAS FOR MOLECULES
LEWIS FORMULAS FOR POLYATOMIC IONS
An example: NH4+
In most of their compounds, the representative elements achieve noble gas configuration
OCTET RULE: elements tend to reach a maximum 8 electrons in the outermost shell - lowest energy/stable configuration (Except for H: 2 electrons)
H •F•••
••••
This rule is not always correct, there are some exceptions
OCTET RULE
In most of their compounds, the representative elements achieve noble gas configuration
OCTET RULE: elements tend to reach a maximum 8 electrons in the outermost shell - lowest energy/stable configuration (Except for H: 2 electrons)
H •F•••
••••
OCTET RULE
How can we calculate the number of shared electrons in a compound?
How can we calculate the number of shared electrons in a compound?
S= N - AS: number of shared electrons
N: the total number of valence electrons needed by all the atoms in the molecule or ion to achieve noble gas configurations
A: the number of valence electrons of all of the atoms. (so it should be the group number?)
N = 8 numbers of atoms that are not H + 2 number of H atoms
Some examples?
HF:
N = 8×1 (1 atom F) + 2×1 (1 atom
H) = 10
A = 7×1 (1 atom F) + 1×1 (1 atom
H) = 8
S = N-A = 10-8 = 2 e- sharedH •F•
••
••••
CO2:
N = 8×2 (2 atom O) + 8×1 (1 atom
C) = 24
A = 6×2 (2 atom O) + 4×1 (1 atom
C) = 16
S = N-A = 24-16 = 8 e- shared
Some examples?
H2O: N =
A =
S =
NH4+: N =
A =
S =
How to draw a Lewis structure with single bonds
Select a skeleton for molecules or ionsStep 1
Calculate the shared electrons (S)
Put the shared electrons into the skeleton
Step 2
Step 4Put the unshared electrons into the skeleton to fulfill Octet rule
Step 3
Select a skeleton for molecules or ionsStep 1
A) The least electronegative element is usually the central element
B) Oxygen atoms do not bond to each other: don’t put them close to one another
How to draw a Lewis structure
C) Hydrogen usually bonds to an O atom, not to the central atom
D) For ions or molecules that have more than one central atom, the most symmetrical skeletons possible are used.
How to draw a Lewis structure with single bonds
Select a skeleton for molecules or ionsStep 1
A) The least electronegative element is usually the central element
B) Oxygen atoms do not bond to each other: don’t put them close to one another
E.g. : CS2 S C S
Some exceptions:a) O2 and O3
b) Peroxides : O22-;
c) Superoxides: O2
-
E.g. : SO4-
O S
O
O
O
How to draw a Lewis structure
Select a skeleton for molecules or ionsStep 1
C) Hydrogen usually bonds to an O atom, not to the central atom
Some exceptions:H3PO3 and H3PO2
D) For ions or molecules that have more than one central atom, the most symmetrical skeletons possible are used.
E.g. : Nitrous acid HNO2 H O N O
How to draw a Lewis structureHow to draw a Lewis structure with single bonds
Some examples: draw a Lewis structure of
a) H2SO4 b) ClO4 c)NO3
a) H2SO4
Step 1: Draw a skeleton
Step 2: Calculate number of shared electronsN= 8×4 (4O) + 8×1 (1S) + 2×2 (2H) = 44
A= 6×4 (4O) + 6×1 (1S) + 1×2 (1H) = 32
Number of shared electrons:S= N-A = 12 e-
How to draw a Lewis structureHow to draw a Lewis structure with single bonds
OH O S O H
O
a) H2SO4
Step 3: put the shared e- in the skeleton
Step 4: put the unshared e- in the skeleton..
..
..
..
..
..
...... ..
Some examples: draw a Lewis structure of
a) H2SO4 b) ClO4- c)NO3
-
How to draw a Lewis structure with MULTIPLE bonds
Select a skeleton for molecules or ionsStep 1
Calculate the shared electrons (S)
Put the shared electrons into the skeleton
Step 2
Sometimes after step 4, a central atom does not have an octet: MAKE MULTIPLE BOND by changing a lone pair into a bonding pair
change 1 pair: from single bond to doublechange 2 pairs: double to triple
Put the unshared electrons into the skeleton to fulfill Octet rule
Step 3
How to draw a Lewis structure with MULTIPLE bonds
Sometimes after step 4, a central atom does not have an octet: MAKE MULTIPLE BOND by changing a lone pair into a bonding pair
change 1 pair: from single bond to doublechange 2 pairs: double to triple
After STEP 4:Move a
lone pair to
bonding pair
Practice: draw a Lewis structure of some hydrocarbon
How to draw a Lewis structure
Lewis structures for Exceptions to the Octet Rule: self-study, further reading in Principle of General Chemistry.
CH4 C2H6 C2H4 C2H2
Sometimes, there COULD be 2 Lewis structure for 1 molecule
RESONANCE
They are not correct structure; the bonds should be between O-O and O=O “one-and-a-half” bond
Resonance structures
RESONANCE: DELOCALISATION
Resonance structures
• Resonance structures are not real bonding, so to depict something in between, RESONANCE HYBRID is used.
In Resonance hybrid, electron-pair delocalisation occur
RESONANCE: DELOCALISATION
Another example of electron-pair delocalisation
Highlight:
• Lewis structure
• Octet rule
• Molecular
geometry
PART 2: MOLECULAR SHAPE
CONCEPTS Octet rule How to draw a LEWIS structure VSEPR (Valence-Shell Electron Pair Repulsion) theory Determine the molecular shape by VSEPR
MOLECULAR SHAPE (GEOMETRY)
VSEPR MODEL : the valence-shell electron-pair repulsion.
VALENCE BOND THEORY
SHAPE
BONDING
• The valence-shell electron-pair repulsion model (VSEPR) can be used to construct the molecule shape from Lewis structure.
• VSEPR THEORY: each group of valence electrons around a CENTRAL ATOM is located as far away as possible from the others in order to minimize repulsions.
• Electron group: regions around the central atom where electrons are likely to be found
MOLECULAR SHAPE (GEOMETRY)
• So valence electron groups can be: Single bond Double bond Triple bond A lone pair Or even a lone electron
Electron group: regions around the central atom where electrons are likely to be found
MOLECULAR SHAPE (GEOMETRY)
• Each group REPEL each other to minimise energy increase BOND ANGLE
Is the structure of a covalent compound is ALWAYS flat?
NO, because there are repulsion between bond pair/ lone pair
• According the valence-shell electron-pair repulsion theory (VSEPR), these repulsions give rise to 5 geometric arrangements.
MOLECULAR SHAPE (GEOMETRY)
VSEPR MODEL
5 geometric arrangements
MOLECULAR SHAPE (GEOMETRY)
Valence electron groups defy the arrangement
Bond angle: is the angle formed by the nuclei of two surrounding atoms with the nucleus of the central atom at the vertex (top of angle).
MOLECULAR SHAPE (GEOMETRY)
• The valence-shell electron-pair repulsion model (VSEPR) can be used to predict the shape of an ABn molecule when A is a main group element.
AXnEwhere A = central atom, main group
elementX = outer atom(s), E: lone pair(s)n = # of “B” atoms
MOLECULAR SHAPE (GEOMETRY)• So remember we have 5 molecular shape
Linear Arrangement
• The molecular shape with 2 electron groups
• 2 electron groups are as far apart as each other
• Linear arrangement of electron groups
Linear shape bond angle of 180o
Linear Arrangement• The molecular shape with 2 electron
groups• Gaseous Beryllium Chloride (BeCl2)
• Carbon dioxide (CO2)
Remember: only electron groups around CENTAL atom influence shape
Trigonal planar Arrangement• The molecular shape with 3 electron
groups• 3 electron groups repel
each other• Trigonal arrangement of
electron groups Trigonal planar shape bond angle of 120o
• Electron groups can be: bonds (single and double) and lone pair
Trigonal planar Arrangement• The molecular shape with 3 electron
groups• Boron trifluoride (BF3)
• The nitrate ion (NO3-)
Trigonal planar Arrangement• The molecular shape with 3 electron
groups• Boron trifluoride (BF3)
• The nitrate ion (NO3-)
Trigonal planar Arrangement
• The bond angel change when 3 electron groups are not identical:
If one of them is a DOUBLE BOND
If one of them is a LONE PAIR
• Let’s examine
The effect of double bond on bond angle
The effect of a lone pair on bond angle
Trigonal planar Arrangement
Example: formaldehyde (CH2O)
The effect of double bond on bond angle
The actual bond angles deviate from the ideal because • the double bond with its greater electron density repels the two single bonds more strongly than they repel each other.
Trigonal planar Arrangement
The effect of lone pair on bond angle When one of the groups is a lone pair, the shape is BENT, or V-shaped
A lone pair can have a major effect on bond angle
Gaseous tin(II) chloride
a lone pair repels bonding pairs more strongly than bonding pairs repel each other. This stronger repulsion decreases the angle between bonding pairs.
Tetrahedral Arrangement• The molecular shape with 4 electron
groups
Tetrahedral Arrangement
• The molecular shape with 4 electron groups
• With 4 electron groups the molecule shape is in 3D.
• So, Lewis structures do not depict all shape
• Consider: Methane (CH4)
All molecules or ions with four electron groups around a central atom adopt the tetrahedral arrangement
Tetrahedral Arrangement
Tetrahedral Arrangement
Example: NH3
Tetrahedral Arrangement
Example: H2O
Tetrahedral Arrangement: BOND ANGLE
BOND ANGLE
< <Electron-pair repulsions cause deviations from ideal bond angles in the following order:
Trigonal bibyramidal Arrangement• The molecular shape with 5 electron groups
• Examples can be found in text books
Octahedral Arrangement• The molecular shape with 6 electron
groups
VSEPR MODEL: MORE EXAMPLES
STEPS TO DETERMINE A MOLECULAR SHAPE by VESPR MODEL
• We understood how VESPR works for the molecule shape
• Now we learn to apply the model and determine a molecule shape from a molecular formula
STEPS TO DETERMINE A MOLECULAR SHAPE by VESPR MODEL
Write the LEWIS structureStep 1
Choose suitable: Count the number of electron group then choose shape
Predict the ideal bond angle+ the direction of any deviation
Step 2
Step 4 Draw and name molecular shape
Step 3
STEPS TO DETERMINE A MOLECULAR SHAPE by VESPR MODEL
Step 1
Example 1: PF3
Step 2
Step 3 Step 4
MOLECULAR SHAPE & DIPOLE MOMENT
•So we now know that molecules have different shapes•The shape influence the overall dipole moment
COVALENT BOND THEORY
Self study /further reading!
Hybrid orbital interacts
Hybrid orbitals
Sigma and Pi bonds
PART 1: CHEMICAL BOND
Highlight:
• Covalent bond
• Ionic bond
• Metallic bond
THIS WEEK
CONCEPTS Valence electron Lewis dot formula Electronegativity Polar, non polar bond Polarity Dipole, dipole moment
Highlight:
• Lewis structure
• Octet rule
• Molecular
geometry
THIS WEEK
PART 2: MOLECULAR SHAPE
CONCEPTS How to draw a LEWIS structure Octet rule VSEPR (Valence-Shell Electron Pair Repulsion) theory Determine the molecular shape by VSEPR