Organic Chemistry

How do you determine the number of protons in an atom?

The number of protons in an atom is equal to its atomic number, which is located above the element symbol.

How do you determine the number of neutrons in an atom?

The number of neutrons in an atom can be found by subtracting the atomic number from the atomic mass.

How do you determine the number of electrons in an atom?

The number of electrons in a neutral atom is equal to the number of protons, which is determined by the atomic number.

How do you draw ionic lewis structures from molecular formulas?

First, identify the cations and anions in the compound. Then, depict the transfer of electrons from the metal to the non-metal, ensuring that the valence shell of each atom is filled according to the octet rule.

How do you identify anions and cations in an ionic compound?

cation: usually metal, loses electrons

anion: usually nonmetal, gains electrons

How do you draw covalent Lewis structures from molecular formulas?

Count total valence electrons, choose central atom (least electronegative, never H), connect atoms and satisfy octets, check formal charges.

How do you use electronegativity properties to predict bond dipole arrows and molecular polarity?

Bond dipole points toward more electronegative atom.

Larger E.N. difference = stronger dipole

dipoles add up => polar molecule

dipoles cancel (symmetrical) => nonpolar molecule

How do you determine formal charge?

Formal charge= # of valence electrons - (atoms attached + dots)

What is the orbital geometry of sp³ hybrid orbital?

Tetrahedral, 109.5 degrees

What is the orbital geometry of the sp² hybrid orbitals?

Trigonal planar, 120 degrees

What is the orbital geometry of the sp hybrid orbital?

Linear, 180 degrees

How do you determine orbital sybritization?

write “sppp”, cross out a p every for every pi bond or more.

for example, a single bond would be sp³, a double bond would be sp², and triple bond or two double bonds would be sp.

What does VSEPR theory tell us about the # of electron groups and their corresponding shapes & bond angles?

linear (2 e groups) → 180 degrees

trigonal planar (3 e groups) → 120 degrees

tetrahedral (4 e groups) → 109.5 degrees

trigonal pyramidal (3 bonds, 1 lone pair) → 107 degrees

bent (2 bonds, 2 lone pairs) → 104.5 degrees

A single line in a lewis structure represents a ___ bond.

sigma

A double line in a lewis structure represents a ___ bond.

pi

what orbitals are present in sigma bonds?

overlap of hybrid orbitals or s orbitals (head on overlap)

what orbitals are present in pi bonds?

overlap of unhybridized p orbitals (side by side overlap)

identify this functional group

Halide

identify this functional group (*R= any carbon based group)

Alcohol (hydroxy)

identify this functional group

Ether

identify this functional group

Thiol

identify this functional group

Sulfide

identify this functional group

Disulfide

how do you identify a carbonyl?

Carbonyls have carbons double bonded to oxygen. This does not include Amides; you can identify the difference because amides also have a Nitrogen bonded to the Carbon.

identify the functional group

Aldehyde

identify the functional group

carboxylic acid

identify the functional group

Ester

identify the functional group

Acyl Halide

identify the functional group

Anhydride

identify the functional group

Ketone

identify the functional group

Amine

identify the functional group

Amide

How do you decide whether to classify halides and alcohols as primary, secondary, or tertiary?

track the carbon that the functional group is connected to and count the number of carbons that it’s attached to (1= primary, 2= secondary, 3= tertiary)

How do you decide whether to classify amines as primary, secondary, or tertiary?

Count the number of R (carbon based) groups connected DIRECTLY to the nitrogen.

What are the characteristics of Arrhenius acids and bases?

Acid → produces H+ in water

Base → produces OH- in water

What are the characteristics of Bronsted-Lowry acids and bases?

Acid → donates H+

Base → accepts H+

What are the characteristics of Lewis acids and bases?

Acid → accepts electron pair

Base → donates an electron pair

Predict the product of the Arrhenius acid-base

H+ moves from acid to OH-, making H2O, and the leftover ions form the salt. (MEMORY TIP: WATER)

Predict the product of the Bronsted-Lowry acid-base

H+ transfer from acid to base, products are conjugate base and conjugate acid. (MEMORY TIP: PROTON MOVE)

Predict the product of the Lewis acid-base

Electron pair moves from base to acid, forming a bonded complex (MEMORY TIP: ELECTRON PAIR MOVE)

What is the relation between Ka, Keq, and pKa and strong acids/bases?

Ka= acid dissociation constant (acid strength)

Larger Ka → stronger acid

pKa= -log(Ka)

smaller pKa → stronger acid

Keq: favors formation of weaker acids and bases

How do you use CARIH to compare acid/base strength?

(Charge, Atom, Resonance, Induction, Hybridization)

Charge: more + → stronger acid, more - → stronger base

Atom: larger/more electroneg. atom stabilizes charge → stronger acid

Resonance: more stabilization (charge/electrons are spread out over mult. atoms) → stronger acid, weaker base

Induction: electron withdrawing groups stabilize charge → stronger acid

Hybridization: more s-character (sp > sp² > sp³) → stronger acid

in a line-bond formula, what do line intersections and ends represent?

Carbon atoms

how are double bonds and triple bonds depicted in line-bond formula?

like usual, two lines for double and three lines for triple

How can you tell how many Hydrogens are attached to Carbon in line-bond formula?

Assume each Carbon has 4 total bonds, so a Carbon with 2 lines has 2 H’s, C with 3 lines has 1 H, C with 4 lines has 0 H’s.

What is a heteroatom and how are they depicted in line-bond formula?

O, N, and halogens depicted by writing them explicitly, with H’s SHOWN if attached

how do you draw valid constututional isomers?

Same molecular formula, rearrange atom connectivity, keep normal valences, avoid duplicates (rotate/flip to check)

how do you determine degrees of unsaturation?

ring or double bond → 1 DoU

triple bond → 2 DoU

how do you name alkanes using IUPAC nomenclature

1. Identify the parent chain (longest carbon chain)

2. Number the chain to give substituents (branches) the LOWEST NUMBERS

3. Name substituents (methyl, ethyl, etc) with their positions

4. Use prefixes (di-, tri-) for multiples

5. List substituents alphabetically + parent name

identify the branched alkyl chain: straight 3 carbon chain, branch attached at end

n-propyl (n= normal/straight)

identify the branched alkyl chain: straight 3 carbon chain, branch attached middle carbon

isopropyl (iso= one branch)

identify the branched alkyl chain: straight 4 carbon chain, branch attached at end

n-butyl (n= normal/straight)

identify the branched alkyl chain: straight 4 carbon chain, branch attached second carbon

sec-butyl (sec= attached to secondary carbon)

identify the branched alkyl chain: branched chain, attached at end carbon

isobutyl (iso= one branch)

identify the branched alkyl chain: central carbon attached to three methyl groups

tert-butyl (tert= attached to tertiary carbon)

How do you decide whether to classify carbons as primary, secondary, tertiary, or quaternary?

Count how many other carbons are attached to the carbon.

Primary → C bonded to 1 other C

Secondary → C bonded to 2 other C’s

Tertiary → C bonded to 3 other C’s

Quaternary → C bonded to 4 other C’s