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 Pg 242

Ionic vs. Covalent Bond Nonmetals share e- forming overlapping valences that keep atoms together –Overlap forms a new shape=molecule Metals give e-; Nonmetals take e-; electrostatic attraction created keeps atoms together –Ions “stick” together = formula unit 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

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 Venn diagram

Try N bonding with H Draw Lewis structure for new molecule. Draw Lewis symbol for N & H How will they share electron pairs??? Pg

Try matching up carbon with hydrogen…

Drawing Lewis Structures “step by step” example…PCl 3 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

Lewis Structure Practice Cl 2 NF 3 HF CHCl 3 (C is central) Ions have a charge. How will this change your total # of valence electrons??? sulfate ion chlorate ion

Equivalent Resonance Structures Draw Lewis Structure for: SO 3 Pg

VESPR Valence 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

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 Linked Pg

1) draw each Lewis structure 2) determine the # of electron domains around the CENTRAL ATOM 3) how many electron domains are bonding sites? H2OCH4 NH3

4 electron domains = electron domain geometry is tetrahedral BUT with 4 bonds3 bonds2 bonds the molecular geometry is TetrahedralTrigonal Pyramidal Bent

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 Linked

Polarity 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 Pg

How “puller” is polar? use electronegativity values to determine the extent of the polarity to be “puller” difference MUST be greater than 0.4 non-puller polar bear puller polar bear Example: Determine extent of polarity of a B – Cl bond Pg

Dipole Moments Which of the following bonds is the most polar? Which one is Non-polar? Cl – ClH – O C – OBr – F N – H C – H

Molecular Polarity Dipole moment of multi-atom molecules depends on BOTH polarities of individual bonds and molecular geometry Pg 265

Molecular Polarity pola r non- polar

Polarity results in …. Intermolecular Attraction Dipole-Dipole - of one molecule attracts to the of another Pg 265

Ion – Dipole attraction Attraction of ionic charge and partial dipole charge of a polar molecule Pg 265

How do compounds dissolve??? Linked ion–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

Prefixes 1 mono2 di3 tri 4 tetra5 penta6 hexa 7 hepta8 octa9 nona 10 deca SO… CO SF 6 N 2 O P 2 O 3 Pg

Practice Cl 2 O 3 BrF 3 I 2 O 4 SO 3 dihydrogen monosulfide Iodine monobromide Nitrogen monoxide Chlorine dioxide