Bonding

Types of Bonds•Ionic

•Covalent

•Metallic

Metallic Bonds•Electrons are shared by many atoms

•Electrons free to move

•Two or more metals

Metallic Compounds•Generally high MP

•Hard & lustrous

•Less brittle

•Conductors

Metallic Bonds•No debate about metallic bonds

•Easy to identify

•Will not be discussed

Ionic Bonds•Electrons are transferred from one atom to another creating (+) & (-) ions

•Metal & nonmetal

Ionic Compounds•Held together by electrostatic charge

•Very high MP

•Brittle

Covalent Bonds•Electrons are shared by two atoms

•Two nonmetals

•Weaker than ionic

Covalent Compounds•Low MP

•Two nonmetals

•Flexible

•Some exceptions

Network Covalent or

Macromolecules•VHMP

•Extremely hard

Molecule•Any compound

that can exist as an entity by itself

Distinguishing Bonds•Distinguishing ionic & covalent bonds can be difficult, but generally determined by differenceelectronegativity

Bonds Types•Ionic

•Polar covalent

•Non polar covalent

Bond Types• Ionic: EN > 2.0

• Covalent: EN < 2.0

• Polar Covalent: 0.5<EN<2.0

• Non polar covalent :EN< 0.5

• Nothing is absolute

Coordinate Covalent Bonds

•A covalent bond in which the two

electrons are donated by one atom

Coordinate Covalent Bond

H3N: BF3

H3N-BF3

H3N BF3

Dipole•Polar bonds

•Polar molecules

DipoleH F+ -

Ionic Bonding

-

+

Covalent Bonding

Occurs when electron orbitals

overlap

OrbitalsOn the board

Max 2 e- per orbital

Hybridization•When s, p, and/or d orbitals (electron clouds) mix to make a new type of multi-lobed orbital

Hybrid Orbitals•sp dsp3

•sp2 d2sp3

•sp3

Electron Cloud Repulsion

• In molecules each electron cloud repels other clouds enough to spread as far apart as possible

VSEPR•Valence Shell Electron Pair Repulsion

•Electron pairs repel each other to spread out as much as possible

Bonding OrbitalsType Hybrid VSEPR• 2 lobes sp AX2

• 3 lobes sp2 AX3

• 4 lobes sp3 AX4

• 5 lobes dsp3 AX5

• 6 lobes d2sp3 AX6

VSEPR Orbitals

Bonding Orbital Shape• 2 lobes: Linear 180o

• 3 lobes: Trigonal planar 120o

• 4 lobes: Tetrahedral 109.5o

• 5 lobes: Hexahedral 120&180o

• 6 lobes: Octahedral 90&180o

Draw the Bonding Electron Dot

Diagrams for Each Element

Bonding Electron Dot Diagrams

•Electron dot diagrams that go through 4 singles before any electrons are paired up

1A: 1 single2A: 2 singles3A: 3 singles4A: 4 singles 5A: 1 pair & 3 singles6A: 2 pair & 2 singles7A: 3 pair & 1 single8A: 4 pair

Drill: Equate each of the following:

sp3 AX2 2 lobes

sp AX3 4 lobes

dsp3 AX4 6 lobes

sp2 AX5 3 lobes

d2sp3 AX6 5 lobes

Lewis Dot Diagrams

•Representation of valence electrons and bonds in a molecule or polyatomic ion

Drawing LDDsDraw the bonding electron dot

diagram for each element in the molecule with the element with the most unpaired e- near the center

Drawing LDDs• If there is more than one carbon, connect the carbons by connecting single dots between one carbon & another

Drawing LDDs• Connect a single dot on

one atom to a single dot on another (never two on the same atom)(never connect one dot to more than one other dot)

Drawing LDDs•Repeat connecting the dots until all singled dots are connected making sure to obey the octet rule if possible

Drawing LDDs• Recognize polyatomic ions

•H2CO3: CO3-2 is a

polyatomic ion; thus, the three Os must connect to the C

Drawing LDDs•Redraw the molecule neatly making sure to include all dots

Draw LDDs for:•BeCl2 H2O

•BF3 C2H6

•CH4 C3H6

•NH3 CH2O

Drawing LDDs• Draw EDDs

• Connect Cs if multiple

• Connect single dots

• Recognize Polyatomic Ions

• Redraw neatly

Draw LDDs for:

•H2C2O4

•C4H6

Draw the LDD for:

C4H9NO2

C4H8N2O2

Coordinate Covalent BondA covalent bond in which both electrons are donated by one

atom

Draw LDDs for:

SO4-2

SO2

Resonance Structures

Equally valid Lewis Dot Diagrams for molecules or polyatomic ions that have the same shape.

OO N O

OO N O

-1 -1

Draw LDDs:HNO3

C4H5NO

Draw LDDs for:

•PH3 PO3-3

•KCN C4H8O

Expanded Octets•Sometimes atoms can be surrounded by more than 8 electrons

• Columns 5A-8A

If more atoms are bound to the central

atom than its unpaired electrons,

then split some paired electrons

Example: 5 things bound to P

P P

HintWhen drawing expanded LDDs for polyatomic ion, adjust the charge of the central atom

Draw LDDs for:

•PH5

•SCl5-1

Draw LDDs for:

•PO4-3 P2O7

-4

•K2SO4 C5H8O

Draw LDDs for:BeH2 AlCl3 SO2

CF4 NH3 H2O

Hybridizations

•sp 2 lobes

•sp2 3 lobes

•sp3 4 lobes

Bond Angles

•sp ~180o

•sp2 ~120o

•sp3 ~109.5o

Sigma Bonds()• End to end orbital overlap

• All single bonds are sigma bonds

• All multiple bonds contain one sigma bond

Pi Bonds ()•Side by side orbital overlap

•Multiple bonds contain bonds

Multiple Bonds•Double: 1 & 1

•Triple: 1 & 2

Intermolecular Forces• Weak temporary

attractions between atoms from one molecule to another or another part of a larger molecule

Intermolecular Forces

•Sometimes called:

• Van der Waals Forces

Intermolecular Forces• Hydrogen-bond

• Dipole-dipole

• Dipole-induced dipole

• London dispersion forces

Hydrogen Bond• Strongest of the

intermolecular forces

• Occurs when H is bound to one highly EN element & connects to another

Dipole-Dipole•When two polar molecules connect

Dipole-Induced Dipole

•When a polar molecule gets near a non-polar one, it induces the non-polar one to become polar; thus, they connect

London Dispersion• Instantaneous attraction

for fractions of seconds in which non-polar molecules connect

• Very weak force

Draw Lewis Dot Diagram for:

ICl5

Determine: bond s, hybridization, VSEPR, & shape

Identify as ionic, covalent, or metallic bonds

Na-Cl Fe-CrS-Cl H-Cl

Mg-S C-CN-O Fe-Fe

Draw LDDs for:

HONO H3PO4

CO2 C3H4O2

Draw LDDs & Predict All for:

CF4 NH3

BF3 CO2

SeCl4 XeF4

Draw LLDs & Predict All For:

H3PO4 ICl5

IF3 CO

SeCl4 C4H6O2

Draw LDDs & predict VSEPR, Hybridization,

bond s, & shape of:

XeF4 SCl4

XeO4

List & describe the four types of intermolecular

forces

Draw Lewis Dot Diagrams of:

C4H5NO2