Exam 1

Because an atom is neutral overall the number of protons and electrons are the same

Z- atomic # (# of protons)
A- mass # (#of protons/neutrons)

same atomic # but different mass #

weighted average of all isotopes

expression used to describe the motion of waves in a fluid.

a wave function, or orbital, and is denoted by the lowercase Greek letter psi (ψ)

- the square of the wave function, ψ2, is plotted in three-dimensional space
- describes the volume of space around a nucleus that an electron is most likely to occupy

s, p, d, and f

spherical shape with nucleus at its center

dumbbell shape with two parts or lobes

4/5 have a cloverleaf shape with four lobes

The orbitals in an atom are organized into different layers around the nucleus called electron shells

2

1s orbital, 2 e-

2s, 2px, 2py, 2pz; 8 e-

3s, 3px, 3py, 3pz, and 5 3d; 18 e-

they explain where the orbitals are orientated on an x, y, z axis

a list of the orbitals occupied by its electrons;

lowest energy orbitals fill up first; 1s→2s→2p→3s→3p→4s→3d

Only two electrons can occupy an orbital, and they must have opposite spins

degenerate orbitals are filled one e- at a time before pairing

orbitals equal in energy

in all organic molecules it must have 4 bonds to form stable compounds

a carbon atom bound to 4 atoms are arranged specifically in this shape because it's the most stable because it's lower in energy; has 109 degree angles

Making bonds always releases energy, and breaking bonds always absorbs energy.

outermost e- shell

8 e- in the valence shell; has special stability

loss and gain of an e- to make a bond

atoms/molecules share an e- to bond

neutral collection of atoms held together by covalent bonds

a covalent bond forms when two atoms approach each other closely and a singly occupied orbital on one atom overlaps a singly occupied orbital on the other atom

are formed by the head-on overlap of two atomic orbitals along a line drawn between the nuclei

1 kJ = 0.2390 kcal; 1 kcal = 4.184 kJ

optimum distance between nuclei that leads to maximum stability

4 regions of e- density, sigma bond, tetrahedral ~109.5 degrees

bonds by sharing two electron pairs between atoms

bonds by sharing three electron pairs between atoms

3 regions of e- density, 1 pi bond, trigonal ~120 degrees

the unhybridized p orbitals interact by sideways overlap

2 regions of e- density, 2 pi bonds, linear ~180 degrees

describes covalent bond formation as arising from a mathematical combination of atomic orbitals on different atoms to form molecular orbitals; orbitals belong to molecule not a lone atom

electrons in this MO spend most of their time in the region between the two nuclei

any electrons it contains can’t occupy the central region between the nuclei

the bonding electrons are attracted more strongly by one atom than the other so that the electron distribution between atoms is not symmetrical

causes bond polarity; the intrinsic ability of an atom to attract the shared electrons in a covalent bond

Electronegativity generally increases from left to right across the periodic table and increases bottom to top

EN differs by less than 0.5

EN differs by 0.5 to 2

EN differs by more than 2

crossed arrow; arrow points in the direction of the e- rich area(δ–) and the tail is in the e- poor area(δ+)

the shifting of electrons in a σ bond in response to the electronegativity of nearby atoms

dipole moment

μ, the magnitude of the charge Q at either end of the molecular dipole times the distance r between the charges, μ = Q × r

Look for any lone-pair electrons, and identify any atom with an electronegativity substantially different from that of carbon. (Usually, this means O, N, F, Cl, or Br.) Electron density will be displaced in the general direction of the electronegative atoms and the lone pairs.

specific atoms within a molecule, particularly atoms that have an apparently “abnormal” number of bonds

(# valence e-) - (# bonding e-/2 + # of nonbonding e-)= formal charge

the change in structural drawing due to the placement of the π and nonbonding valence electrons; the connections between atoms are the same, and the three-dimensional shapes are the same.

molecules have single unchanging structure and are hybrids of individual resonance forms and has characteristics of all

Look for three-atom groupings that contain a multiple bond next to an atom with a p orbital. Then exchange the positions of the multiple bond and the electrons in the p orbital.

donates a hydrogen ion, H+

accepts the proton, H+

accepts e-

donates e-

strong acid

weak acid or base

smaller= stronger acid

lone pairs or neg charge means its basic; any trivalent N is a base

ARIO and ERIH

Atom- which atom is H bound to?
Resonance- which conjugate base has resonance?
Inductive effects- which compound has more? EN
Orbital- which orbital is making bond with H?

Element
Resonance
Inductive effects
Hybridization

more s-character=most stable; sp3=25% s-chara; sp2=33% s-chara; sp= 50% s-chara

Vander waals (london dispersion forces)- anything with e- has these
dipole-dipole moment- need polar bonds
H-bonding- H bound to O, N, F

H- 1 bond
C- 4 bonds
N- 3 bonds
O- 2 bonds
X- 1 bond

a group of atoms within a molecule that has a characteristic chemical behavior

have a double bond; naming end in -ene

have triple bond; name ending in -yne

single bond between carbons; end in -ane

have alternating double and single bonds in a six-membered ring; end in -yl benzene

Halide, haloalkane; starts with halo-

Ether; ends with ether

Monophosphate, phosphate

Diphosphate; diphosphate

Imine

Amine; -amine

Nitrile, -nitrile

Thiol; -thiol

Sulfide; sulfide

Disulfide; disulfide

Sulfoxide; sulfoxide

Aldehyde; -al

Ketone; -one

Carboxylic acid; -oic acid

Ester; -yl -oate

Thioester; -yl -thioate

Amide; -amide

Acid chloride; -oyl chloride

Acid anhydride; -oic anhydride

Epoxide; -ene oxide

Acyl halide; -oyl (halide)

Isocyanate; -yl isocyanate

Azo compound; azo-

meth-, eth-, prop-, but-, pent-, hex-, hept-, oct-, non-, dec-

bonded to 3 H

bonded to 2 H

bonded to 1 H

no H bonded

Locant (where sub)-prefix(sub name)-parent(longest carbon chain)-suffix (primary FG)

isopropyl sub

sec-butyl sub

isobutyl sub

tert-butyl sub

isopentyl sub

neopentyl sub

t-pentyl sub

different arrangement due to bond rotation

most stable, give elements more room

causes tortional strain

4 kJ/mol each

6 kJ/mol each

energy require to rotate, in projections it is the highest energy conformation value

Gauche(steric strain), 3.8 kJ/mol

11 kJ/mol each

large constituents on opposit sides

is the repulsive interaction that occurs when atoms are forced closer together than their atomic radii allow

with atoms connected in the same order but differing in three-dimensional orientation

different connections between atoms

cis- on the same dimensional plane trans- diff dimensional planes

the strain due to expansion or compression of bond angles

the strain due to eclipsing of bonds between neighboring atoms

ΔE = –RT ln K

gas constant 8.315 J/(molxK)

strain between an axial subsituent and the axial hydrogens