Module 1 Core Ideas

Atomic Valence

highest full shell= stability

Unpaired electrons….

= bonds

electron pairs…..

= lone pairs

Ionic Bonds

transfer of valence e- ; creates cations & anions

Covalent Bonds

share valence e- ; no ions formed

Pure Covalent Bonds

formed between atoms of identical electronegativity

Polar Covalent Bonds

between atoms w/ DIFFERENT electronegativity; unequal sharing

Ionic Bond Characteristics (4)

High MP, Brittle Crystal Solid, Dissolve in polar solvents, Aqueous solutions conduct electricity

Covalent Bond Characteristics (4)

MP Under 300C, SLG, water insoluble range of solubility, Aqueous solutions do not conduct electricity

Carbon forms more____ bonds

covalent

Carbon is catenation?

yes, it likes to self bond

"notice in diagrams bonds with C and shares e- w/ H"

Bond order/ multiple bond

= # of bonds between atom pair in molecule

Single Covalent bond makes _____ bond order

low bond order

more bonds + less H (or additional atom) =

unsaturation

Unsaturation includes

double bonds, triple bonds, rings

Isomer

molecules w/ same number & atom type & different atom arrangement

Heteroatoms

atoms other than C or H; bonded in functional groups

Condensed Formulae

atoms w/ no bonds, may include branch

Bond line formulae

all bonds no atoms except heteroatoms and heteroatoms w/ H

Group # - (Dots + Dashes)

Formal Charge

For C forming 4 bonds its identified as ____ n..?

electrically neutral

C with 3 bonds and a lone pair makes ____ charge

negative charge, anionic

C with 3 bonds makes _____ charge

positive charge, cation

Hybrid Structure for Resonance Formation

blend of all individual resonance structures

Curve Arrow Notation

moves lone pair to multiple bond

______ are more representative of the overall hybrid structure

Major contributors

End overlaps produce

sigma bonds

Sideway overlaps produce

pi bonds

C combines orbitals, creating 4 valence electrons

4sp3

Valence Shell Electron Pair Repulsion

determines the shape around atoms in molecules based on the electron pattern