What happens if interacting things do not want to give?

They must share…

What does it mean to share an e- ?– shared e- “belongs” to both atoms– both complete octets– valence energy levels of overlap

• the sharing/overlap binds the atoms together and is called a covalent bond

Linked

Linked

Pg 309-311

Ionic vs. Covalent Bond

• Metals give e-; Nonmetals take e-; electrostatic attraction created keeps atoms together– Ions “stick” together = formula unit

• Nonmetals share e- forming overlapping valences that keep atoms together– Overlap forms a new shape=molecule

Write in the box How are these diagrams different?

Drawing Bonding

Venn diagram model

Draw Lewis symbol for Cl

Is one Cl noble gas stable?

Lewis Structure show shared pair(s) as line and unshared pairs as dots

single line = “single bond”Pg 309-311

Draw Lewis symbols for each atom of water then match up the electrons to make bonds!

Draw its Lewis structure

overlap creates a new molecule with its own shape

What about water???

Pg 309-311

Venn diagram

Try N bonding with H

• Draw Lewis structure for new molecule.

Pg 309-311

• Draw Lewis symbol for N & H

• How will they share electron pairs???

Try matching up carbon with hydrogen…

Drawing Lewis Structures “step by step” example…PCl3

1. Sum valence electrons for all atoms

2. Divide total # of ve- by 2 to give # of electron pairs

3. Determine which atom is the CENTRAL atom???

4. Surround the central atom with 4 electron pairs

5. Put the other atoms around the central atom

6. Use the remaining pairs to complete octets around each remaining atom

7. If there are not enough electron pairs to provide an octet for each atom, move nonbonding electron pairs between 2 atoms that already share a pair

Pg 317-319

PCl3 is used to make numerous phosphate compounds for industrial purposes one of which is PSCl3

which is then used to make parathion which is used as an insecticide

Lewis Structure PracticeCl2 NF3

HF CHCl3 (C is central)

Ions have a charge. How will this change your total # of valence electrons???

sulfate ion chlorate ion

Multiple Bonds

sigma (σ) bond - covalent bond in which electron density is concentrated along the internuclear axis

pi (π) bond - results from the overlap between two p orbitals oriented perpendicularly to the internuclear axis

Equivalent Resonance Structures

Draw Lewis Structure for:

SO3

Pg 322-325

Equivalent Resonance Structures

Draw Lewis Structure for:

CO3-2

Non-Equivalent Resonance Structures

What if you can draw two completely different Lewis Structures each following the octet rule, which one is most reasonable???Draw 2 different Lewis structures for:

CO2 “carbon dioxide”

Formal Charge

charge difference between valence electrons of each isolated atom and number of electrons assigned to atom in a specific Lewis Structure

The best structure has (1) the fewest formal charges and (2) the negative charge on the most electronegativity atom

Pg 320-321

VESPRValence Electron Shell-Pair Repulsion

• Electron domain – region about a central atom in which electrons are likely to be found ((bonding AND nonbonding))

• Bonding electrons – electrons shared between atoms

• Nonbonding electrons (lone pairs) – electrons that are not shared but are needed to complete atoms octet

Pg 346-357

VESPR• Electron domains (lone pairs and bonds)

will orient naturally to “try to get out of each other’s way”

• The best arrangement of a given number of electron domains is the one that minimizes the repulsion among them

• 3-d shape depends on the bond angles resulting from domain arrangement

Pg 346-357

Linked

1) draw each Lewis structure 2) determine the # of electron domains around the CENTRAL ATOM 3) how many electron domains are bonding sites?

H2O CH4

NH3

Hybrids A hybrid results from combing

two of the same types of things giving characteristics of both

• Hybridization explains bond angles and resulting geometries

• shape of a hybrid orbital is different from original

• total number of atomic orbitals remains constant

sp hybridization (example BeF2)

Be no single electrons

F 1 single electron

if Be “promotes” an electron

Then 2 single electrons are available.

BUT one s and one p would give not give the predicted symmetrical linear geometry.

sp hybridization (example BeF2)

SO valence-bond theory says they “mix” to create 2 new AND identical sp orbitals creating symmetrical geometry

Be now

has 2 identical/symmetrical

sp orbitals that can overlab

with F’s 2p orbitals

Link

sp2 hybridization

sp3 hybridization

Link

sp3d & sp3d2 hybridization

When sharing, why would one interacting thing get more than another???

Electronegativity - ability of an atom in a molecule to attract electrons to itself (electron affinity)

Pg 312-317

Linked

PolarityPg 312-317 Linked

•Polar (“puller”) – atoms pull electrons differently; results in uneven distribution

–Gives bond partial positive and partial negative “dipoles”

• Nonpolar – atoms pull electrons equally; results in even distribution

How “puller” is polar?

use electronegativity values to determine the extent of the polarity

to be “puller” difference MUST be greater than 0.4

Pg 312-317

non-puller polar bear

puller polar bearExample: Determine extent of polarity of a B – Cl bond

Dipole Moments• Which of the following bonds is the most

polar? Which one is Non-polar?

Cl – Cl H – O

C – O Br – F

N – H C – H

Molecular Polarity Dipole moment of multi-atom molecules depends on BOTH polarities of individual bonds and molecular geometry

Pg 263-266

Molecular Polarity

polar

polar

polar

non-polar

non-polar

Polarity results in ….Intermolecular Attraction

Dipole-Dipole - of one molecule attracts to the of another

Pg 445-446

Hydrogen bondingdipole-dipole attraction of H in a polar bond to an F, O, or N in another molecule

H bonding is stronger than regular dipole-dipole due to an unshared electron pairLinked

Pg 449-451

Hydrogen bonding of water

Pg 449-451

Ion – Dipole attraction

Attraction of ionic charge and partial dipole charge of a polar molecule

Pg 445-446

How do compounds dissolve???Linkedion–dipole attraction separates NaCl formula units into isolated ions

dipole-dipole attraction cause water molecules to surround and isolate sugar molecules

Naming Binary Molecular Compounds

• element furthest to the left on table should be written first

• if same group element with higher atomic # should be written first

• second element name should end with “ide”

• Greek prefixes designate # of atoms of each element

((prefix mono is NOT used for first element)))

Pg 66-67

Prefixes

1 mono 2 di 3 tri

4 tetra 5 penta 6 hexa

7 hepta 8 octa 9 nona

10 deca

SO…

CO SF6 N2O P2O3

Pg 66-67

Practice

• Cl2O3 BrF3

• I2O4 SO3

• dihydrogen monosulfide

• Iodine monobromide

• Nitrogen monoxide

• Chlorine dioxide