Unit 3: Organic Chemistry
What does the term organic mean to you?
 wholesome, not artificial
 foods that are grown entirely through
natural processes
o no synthetic materials like dyes, chemicals that
ripen fruit, pesticides, artificial sweeteners, etc.
o no antibiotics or hormones given to animals to
make their milk of muscle production increase
What does the term organic mean to a chemist?
 compounds containing carbon (& hydrogen)
 molecular compounds that are (or were) linked to
living things
o ex: animals, plants, fossil fuels like gasoline
o not minerals (like Na, Cl, Ag, Mg, etc.)
 pairs of electrons are shared, not transferred like
inorganic (ionic) compounds
o non-metals, not metals
organic chemistry = the chemistry of carbon-based
compounds (and hydrogen)
 non-metal compounds that share e–
 opposite is inorganic (what we’ve been studying for
the most part over the last few months)
o anything that doesn’t contain both carbon &
hydrogen
 ex: NaCl, K3PO4, H2SO4, MgBr2, etc.
 examples of consumer products that are made from
complex organic compounds = shoes, medications,
computers, make-up
 naturally-found organic compounds = foods, perfumes
 the majority of compounds we use in everyday life are
organic
o ex: fuels, sugar, alcohol, plastics, Styrofoam, nylon,
polyester, …
 organic compounds are very useful, but also very
hazardous, to humans & their environment
o they’re highly toxic to make and they don’t break
down easily when thrown away (are very stable)
 organic chemistry is important in dentistry (dental
assistant), health care (nursing), vet services (vet tech),
manufacturing (plastics, nylon, etc.), food science,
agriculture, pharmaceuticals, …
o basically anything that uses organic compounds
 ex: look on a chemical bottle, a bottle of pills,
etc. and there will be names of organic
compounds on them
 e.g., 1,3-dichloro-4-ethyl-5-propyl-1cyclopentene
Main goals
 name organic molecules using IUPAC rules
 make a simple organic molecule (called an ester)
 explain the importance of organic compounds in
consumer products
 identify health & environmental issues related to
organic compounds
 read p. 175 of your textbook for some context
Bonding
What’s a bond, anyway?
 aggregates (a bunch) of atoms held together by forces
of attraction
 in order to break the bonds, energy (work) must be
done
o ex: heat energy, electrical energy added to break
the bonds between atoms
Types of Bonding
 like solutes in solution, there are 2 types:
i. ionic bonds
o metal + non-metal
o held together due to force of electrostatic
attraction
o ex: NaCl, CaF2, Ag2O, etc.
o NaCl vs. MgO
 1 e– is transferred in NaCl, whereas 2 e– are transferred
with MgO; therefore MgO has a stronger bond
o NaCl vs. CsCl
 a Cs atom is huge compared to Na, which means more
empty space between Cs and Cl, therefore a weaker bond
ii. covalent (molecular) bonds
o non-metals
o held together by a mutual attraction towards
shared electrons
o very strong molecules
o ex: sugar (C6H12O6), ethanol (C2H5OH), methane
(CH4), propane (C3H8), etc.
Lewis Dot Diagrams
 these are useful to show the sharing that
takes place between atoms in covalent
molecules
 4 types of covalent bonds:
i. 1 covalent bond  1 pair of e– shared
o easiest, most straight-forward
o ex: H2, F2
ii.
2 covalent bonds  2 pair of e– shared
o 2 single bonds or 1 double bond
o ex: H2O, O2
iii. 3 covalent bonds  3 pair of e– shared
o 3 single bonds or 1 double/1 single or 1 triple
o ex: NH3, NOCl, N2
iv. 4 covalent bonds  4 pair of e– shared
o 4 single bonds or 1 double/2 single or 1
triple/1 single or 2 doubles
o ex: CH4, H2CO , HCN, CO2
2D structural diagrams
3D structural diagrams
Electronegativity
 some elements have a tighter hold on their e– than
others
 p. 40 of your textbook shows the electronegativity values
of some elements
 metals generally have a weaker hold on their e– than
non-metals (metals are less electronegative)
o hence why their electronegativity values are lower
electronegativity = ability of an atom to attract a shared
pair of electrons
 the higher the number, the better the element can
attract the e–
Which element has the highest electronegativity?
Fluorine,  it has the greatest ability to attract shared e–
 what is the general trend in electronegativity on the PT?
o see p. 41
 when elements with different electronegativities share
pairs of e–, this causes the molecule to be ‘uneven’
 this unequal sharing results in slight charges at each end
of the bond
o an ‘uneven’ molecule is said to be polar
Polar & Non-Polar Molecules
o every molecule has 2 opposite sides (+ / -), regardless of
its shape
o sometimes atoms that are sharing e– have different
strengths (electronegativities)
o causes a molecule to become slightly charged, aka
polar
polar = slightly charged molecule (uneven)
o due to differences in electronegativity of elements,
non-linear shape, and/or asymmetry of the molecule
o ex: water (H2O)
 oxygen has a high electronegativity (3.5), while
hydrogen’s is low (2.1)
 water is also a non-linear shape
(model kits)
non-polar = uncharged molecule
o atoms with the same electronegativities, molecules
that are symmetrical and/or linear
o ex: methane (CH4)
 tug-of-war analogy
o organic (molecular/covalent) compounds can be either
polar or non-polar
o I lied to you in the solutions unit when I said that ionic compounds
are generally polar and molecular compounds are non-polar (sorry
 --- I was trying to keep things simple)
polar covalent bond = a slightly charged covalent bond
due to atoms with differing electronegativities
non-polar covalent bond = an uncharged covalent bond
o electronegativities are the same or the central atom is
being pulled evenly in all directions
o ex: methane, CH4
Properties of Polar & Non-Polar Molecules
 like dissolves like
o polar dissolves polar
o non-polar dissolves non-polar
 ex: oil & vinegar
o oil is non-polar (uncharged) and vinegar is polar
(slightly charged)
 this is why they don’t mix
 ex: gasoline & water
o these 2 organic substances don’t mix either
o so which is polar, which isn’t?
 gasoline is non-polar, while water is polar
Demo: polarity of water + plastic comb
Organic
 carbon (& hydrogen)
 involves non-metals
only
 e– are shared
 always covalent
bonding
 held together by e–
being shared
 molecules can be very
large
 humans come in
contact with many of
these compounds daily
 useful, but can be very
hazardous to
environment (& health)
Inorganic
 minerals like CaCl2, NaF
 involves metals & nonmetals
 e– are transferred (given
up or taken)
 usually ionic bonding
 held together by +/charges
 molecules are generally
small
 not as commonly used
in daily life
 useful, but can be
hazardous to health (&
environment)
Try This activity, textbook p. 44 (need kits!)