What you really need to remember !




Metric System
Lab safety (WHMIS, household symbols)
Nomenclature (inorganic, organic)
Quantum Theory
Quantity
length
mass
volume
temperature
time
amount of matter
electric current
luminous intensity
Base Unit
metre
gram
litre
kelvin
second
mole
ampere
candela
Symbol
m
g
L
K
s
mol
A
cd
Quantity
Name of Unit
Symbol
in SI Base
Units
density
kilogram per
cubic metre
kg · m-3
kg · m-3
(kg/m3)
force
Newton
N
kg · m · s-2
(kg · m / s2)
pressure
Pascal
Pa
N · m-2
(kg·s-2·m-1 , N / m2)
heat energy
Joule
J
N·m
(kg·m2·s-2 )
Prefix Symbol Multiplication Factor
exa
E
1 000 000 000 000 000 000
peta
P
1 000 000 000 000 000
tera
T
1 000 000 000 000
giga
G
1 000 000 000
mega M
1 000 000
kilo
k
1 000
hecto h
100
deca
da
10
THE BASE UNIT
1
Exponential
Notation
1018
1015
1012
109
106
103
102
101
100
Prefix Symbol Multiplication Factor
Exponential
Notation
THE BASE UNIT 1
100
deci
d
0.1
10-1
centi c
0.01
10-2
milli
m
0.001
10-3
micro μ
0.000 001
10-6
nano n
0.000 000 001
10-9
pico
p
0.000 000 000 001
10-12
femto f
0.000 000 000 000 001
10-15
atto
a
0.000 000 000 000 000 001 10-18


These tables must be memorized.
The quiz will be on ......


The eight-sided outline
(octagonal) signifies that
the contents of the container
is dangerous.
The triangular outline
signifies that the container
is dangerous, usually because
the contents are under high pressure.
Poison
 poisons can enter the body in one of three ways:
a) ingestion (eating)
b) inhalation (breathing)
c) absorption through the skin
d) injection
Corrosive
 are chemicals which can act on clothing, skin,
eyes or internally by drinking or eating
 can cause symptoms ranging from mild rash to
serious skin damage
 can damage clothing
 can cause blindness
 can cause death if ingested
Flammable
 are substances which can burn easily or cause
other materials to burn
Radiation
 radioactive materials emit high energy atomic
particles or high energy radiation (x-rays, gamma
rays), or both
 found in smoke detectors and involve no danger
if kept at a safe distance
Explosive


can cause injury or death
as a result a blast or because
of the materials expelled by the blast (metal
shards)
usually are pressurized aerosol containers which
may explode when heated
Workplace
Hazardous Materials
Information
System

Class A - Compressed Gas

danger lies in the pressure, not in the contents.

Class B - Combustible and
Flammable Material


may burn at relatively low temperatures, burn spontaneously
or as a result of heat, sparks or friction
hydrocarbons and several chemicals like phosphorus, sodium
and calcium carbide would be included in the list.

Class C - Oxidizing Material

may cause a fire, react violently or explode when it comes
into contact with combustible materials such as wood.
an oxidizer supplies the oxygen for a chemical reaction.


Class D, Division 1 –
Poisonous and Infectious Material;
Immediate and Serious Toxic
Effects

these substances have acute toxicity - refers to a substance
which has immediate effects, usually within 24 hours

Class D, Division 2 –
Poisonous and Infectious
Material; Other Toxic Effects

these substances have chronic toxicity - refers to the effects
of a substance through repeated exposure at low levels over a
long period (weeks, months or years).
effects include; organ damage, illness or death
the effects can also include cancer,
allergies or chronic diseases (bronchitis, emphysema,
cirrhosis of the liver, etc.)
long term alcohol or cigarette use would fall under this
category




Class D, Division 3 –
Poisonous and Infectious Material;
Biohazardous Infectious Material

refers to an infectious agent
(bacteria, virus or some other
organism) which may spread disease if improperly handled,
also called a biohazard
this symbol is common in hospital emergency rooms on
containers where used needles and dressings are deposited


Class E - Corrosive Material

causes severe eye and skin irritation upon contact
causes severe tissue damage with prolonged exposure
may be harmful if inhaled
the effects are the same as under the household hazards




Class F - Dangerously Reactive Material

is very unstable
may react with water to release
a toxic or flammable gas
may explode as a result of shock,
friction or increase in temperature
undergoes vigorous polymerization
all of these reactions happen very quickly; you have to be
extremely careful around these substances




1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
No eating or drinking in the lab.
Treat all chemicals as if they were hazardous:
Never perform unauthorized experiments.
Report all accidents immediately.
If you get a chemical solution in your eye go to the eyewash
station immediately and wash the eye for at least 5 minutes.
If you get chemicals on your clothes, wash the clothes
thoroughly.
Do not wear loose clothing during a lab. Tie long hair back.
Do not sit on the lab bench; you do not know how clean it is.
Clean all equipment thoroughly and put it back where it
belongs.
Follow directions concerning the safe disposal of chemicals
and solutions.
Clean your lab station thoroughly after a lab.




Inhaled Poison - Remove the patient to fresh air and
apply artificial respiration if necessary. Keep the victim warm
with blankets.
Contact of Poison with Skin or Eyes - Flood affected area
with water, for at least 5 minutes. Remove contaminated
clothing. DO NOT attempt to use chemical antidote.
Swallowed Poison - If the person is conscious and able to
swallow, immediately dilute the poison by giving the victim 2
to 4 cups of milk or water.
Swallowed Corrosives - DO NOT INDUCE VOMITING.
Give milk and water. If vomiting occurs naturally, hold head
below hips to avoid choking.


Be able to identify the items on the sheet given.
Note: the flask is an erlenmeyer flask

Inorganic
 elements
 molecular
 ionic

Organic
 aliphatic
 cyclic
 substituted

Common substances
 inorganic or organic


must be simple as possible
must be unique


one kind of atom
most are monoatomic (one atom)
 Cu, Fe, Al, He

8 elements are diatomic (2 atoms)
 H2 N2 O2 F2 Cl2 Br2 I2 (At2)

2 are polyatomic
 S8
 P4


known by names other than their systematic
names
be familiar with
 formulas
 systematic name
 common name

know whether systematic or common name
takes precedence
Formula
Chemical Name
Common Name
H 2O
NaCl
HCl
HNO3
H2SO4
H3PO4
CH3COOH
CaSO4
NH3
hydrogen oxide
sodium chloride
hydrogen chloride
hydrogen nitrate
hydrogen sulfate
hydrogen phosphate
acetic acid
calcium sulfate
nitrogen trihydride
water
table salt
hydrochloric acid
nitric acid
sulfuric acid
phosphoric acid
vinegar
gypsum (dry wall)
ammonia
Formula
Chemical Name
Common Name
H2O2
C2H5OH
CH3OH
CH4
O3
C12H22O11
KCl
NaOH
CaO
hydrogen peroxide
ethanol
methanol
methane
ozone
sucrose
potassium chloride
sodium hydroxide
calcium oxide
hydrogen peroxide
drinking alcohol
wood alcohol
natural gas
ozone
table sugar
potash
lye, caustic soda
lime

made up of 2 non-metals bound together with
covalent bonds:


can’t predict formula so naming is done on a
numbering system.
prefixes in front of the element name tell you how
many of that element are present in the compound:
mono
1
hexa
6
di
2
hepta
7
tri
3
octa
8
tetra
4
nona
9
penta
5
deca
10

N2O5
dinitrogen pentaoxide (note ending)

CO2
carbon dioxide

CO
carbon monoxide

Cl2O7
dichlorine heptaoxide
(no mono on first atom)
C
N
O
F
Si
P
S
carbide
nitride
oxide
fluoride
silicide
phosphide
sulfide
Cl
As
Se
Br
Te
I
chloride
arsenide
selenide
bromide
telluride
iodide

tetraphosphorus decaoxide
P4O10

tetrasulfur tetranitride
S4N4

bromine monofluoride
BrF

diarsenic triselenide
As2Se3

made up of cations and anions which come
together as a result of ionic attraction:



there is no molecule, rather a crystal lattice.
chemical formula is ratio of cations to anions in
crystal; formula unit
ionic substances are recognized because they
contain a metal + non-metal



the formula unit of any ionic compound is the
ratio of cations to anions in the crystal lattice.
the net charge of a formula unit is zero.
it is written as the lowest ratio of cations to
anions.






K1+
Mg2+
Al3+
Ca2+
Sr2+
NH41+
F1Cl1S2S2OH1SO42-
gives KF
gives MgCl2
gives Al2S3
gives CaS
gives Sr(OH)2
gives (NH4)2SO4

Do first half of nomenclature assignment
a) K1+, Br1-
f) Zn2+ , O2KBr
b) Ca2+, Cl1c) Li1+, H1-
ZnO
g) Mg2+ , NO31-
CaCl2
h) Fe2+, O2-
LiH
d) Fe3+, OH1e) Ca2+, OH1-
Mg(NO3)2
FeO
i) Fe3+ , O2-
Fe(OH)3
Ca(OH)2
j) Sn4+, F1-
Fe2O3
SnF4
k) Hg2+, O2-
p) Mn7+ , O2HgO
l) K1+, PO43m) Si4+, O2-
K3PO4
q) Na1+, SeO32r) Na1+, SeO42-
SiO2
n) NH41+, SO42s) Al3+, SO42(NH4)2SO4
o) Na1+, PO43t) H1+, S2Na3PO4
Mn2O7
Na2SeO3
Na2SeO4
Al2(SO4)3
H2S
a) ZnSO4
Zn2+ SO42b) Mn(NO3)3
Mn3+ NO31c) SnO
Sn2+ O2d) LiHCO3
Li1+ HCO31e) Hg2Cl2
Hg22+ Cl1-
f) KSCN
K1+ SCN1g) Na2SO3
Na1+ SO32h) Al2(Cr2O7)3
Al3+ Cr2O72i) MgC2O4
Mg2+ C2O42j) SrH2
Sr2+ H1-




cations from groups 1 & 2, Al, Zn, Ag, Cd, NH41+ (all
have only one possible charge)
anions can be anything on the chart (including
polyatomic ions)
only one formula unit possible, so name is a
repetition of the ion names:
NaCl
Na1+
Cl1sodium chloride

NH4NO3
NH41+
NO31ammonium nitrate

Al2(CO3)3
Al3+
CO32aluminum carbonate

Ag3P
Ag1+
P3silver phosphide


cadmium chlorite
Cd2+
strontium nitride
Sr2+
ClO21Cd(ClO2)2
N3-
Sr3N2



used when the cation can have more than one
possible charge
used for all other metals on the Periodic Table.
the name of the compound includes the charge
of the cation in roman numerals, in brackets after
the cation name.
The Stock System of Nomenclature
Formula
Charge of
Cation
Charge of
Anion
Name of
Compound
SnF2
Sn2+
F1-
Tin (II) fluoride
SnF4
Sn4+
F1-
Tin (IV) fluoride
Co(ClO)3
Co3+
ClO1-
MnO2
Mn4+
O2-
US3
U6+
S2-
Cobalt (III)
hypochlorite
Manganese (IV)
oxide
Uranium (VI)
sulfide





older system
much, much, older
largely replaced by Stock system, but is still
around.
if see name be able to give formula.
never give classical name for any formula.
The Stock and Classical Systems of Nomenclature
Charge of Charge of
Formula
Stock Name
Cation
Anion
Classical
Name
SnF2
Sn2+
F1-
Tin (II)
fluoride
Stannous
fluoride
SnF4
Sn4+
F1-
Tin (IV)
fluoride
Stannic
fluoride
CoCl2
Co2+
Cl1-
Cobalt (II)
chloride
Cobaltous
chloride
CoCl3
Co3+
Cl1-
Cobalt (III)
chloride
Cobaltic
chloride
Cu2O
Cu1+
O2-
Copper (I)
oxide
Cuprous
oxide
CuO
Cu2+
O2-
Copper (II)
oxide
Cupric oxide


water molecules physically attached to ionic and
molecular substances.
name and formula recognizes their presence.

gypsum typically attracts 4 water molecules per
formula unit:
CaSO4 · 4 H2O

name the substance then use a numbering prefix
followed by subscript hydrate:
calcium sulfate tetrahydrate
Naming Hydrated Compounds
Formula
Name of Compound
P2O5 · 10 H2O
diphosphorus pentaoxide decahydrate
Na2CO3 · H2O
sodium carbonate monohydrate

Complete second half of nomenclature
assignment
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
11)
12)
13)
14)
15)
NH3
Fe(NO3)2
SO2
MgBr2
GeCl4
N2
AlPO4
C2H5OH
Li2CrO4
KH
CuCr2O7
NH4NO3
H2SO4
Pb3(PO4)2
KSCN
Fe2+ NO31Mg2+ Br1Ge4+ Cl1Al3+ PO43Li1+ CrO42K1+ H1Cu2+ Cr2O72NH41+ NO31H1+ SO42Pb2+ PO43H1+ SCN1-
ammonia
iron (II) nitrate
sulfur dioxide
magnesium bromide
germanium (IV) chloride
nitrogen
aluminum phosphate
ethanol
lithium chromate
potassium hydride
copper (II) dichromate
ammonium nitrate
sulfuric acid
lead (II) phosphate
potassium thiocyanate
16)
17)
CO2
P2O5  6 H2O
18)
19)
20)
21)
22)
23)
PbO
Pb2+ O2BaS
Ba2+ S2S8
Mo(NO3)7
Mo7+ NO31BaH2
Ba2+ H1CaSO4  4 H2O
Ca2+ SO42O2
Al2O3
Al3+ O2PCl3
NO3
Mn2O3
Mn3+ O2U(CO3)3
U6+ CO32SnSO3
Sn2+ SO32-
24)
25)
26)
27)
28)
29)
30)
carbon dioxide
diphosphorus pentaoxide
hexahydrate
lead (II) oxide
barium sulfide
sulfur
molybdenum (VII) nitrate
barium hydride
calcium sulfate tetrahydrate
oxygen
aluminum oxide
phosphorus trichloride
nitrogen trioxide
manganese (III) oxide
uranium (VI) carbonate
tin (II) sulfite
1) sodium fluoride
2) potassium carbonate
3) aluminum sulfide
4) calcium bromide
5) chlorine heptafluoride
6) silver oxide
7) ammonium sulfide
8) barium hydroxide
9) phosphorus
10) mercurous chloride
11) tin (II) nitrate
12) potassium bisulfite
13) caustic soda
14) boric acid
15) cupric sulfate
Na1+ F1K1+ CO32Al3+ S2Ca2+ Br1Ag1+ O2NH41+ S2Ba2+ OH1Hg22+ Cl1Sn2+ NO31K1+ HSO31Na1+ OH1H1+ BO33Cu2+ SO42-
NaF
K2CO3
Al2S3
CaBr2
ClF7
Ag2O
(NH4)2S
Ba(OH)2
P4
Hg2Cl2
Sn(NO3)2
KHSO3
NaOH
H3BO3
CuSO4
16)
17)
18)
19)
20)
21)
22)
23)
24)
25)
26)
27)
28)
29)
30)
calcium carbonate
ammonium sulfite
iron (II) hydroxide
uranium (VI) nitrate
ozone
lithium dichromate
hydrogen nitrate
barium bicarbonate
nitrogen dioxide
carbon monoxide
methanol
ammonium oxalate
argon octafluoride
gold (III) nitrate
cobalt (II) chloride
hexahydrate
Ca2+ CO32NH41+ SO32Fe2+ OH1U6+ NO31Li1+ Cr2O72H1+ NO31Ba2+ HCO31-
NH41+ C2O42Au3+ NO31Co2+ Cl1-
CaCO3
(NH4)2SO3
Fe(OH)2
U(NO3)6
O3
Li2Cr2O7
HNO3
Ba(HCO3)2
NO2
CO
CH3OH
(NH4)2C2O4
ArF8
Au(NO3)3
CoCl2 · 6 H2O

3 types of organic compounds important for this
class:
 aliphatic hydrocarbons - chains
 cyclic hydrocarbons - rings
 aromatic hydrocarbons - benzene rings
Naming hydrocarbons involves looking at 3
aspects:
1. Number of carbons linked in a continuous chain.
2. The presence of single, double or triple bonds in
the carbon chain.
3. The presence of structures other than hydrogen
attached to the main carbon chain (functional
groups).

1
2
3
4
5
6
how many carbons are bonded in a chain gives the
prefix of the name:
methethpropbutpenthex-
7
8
9
10
11
12
heptoctnondecundecdodec-

other prefixes include:
13
14
15
20
25
tridectetradecpentadeceicospentacos-
30
40
50
100
triaconttetracontpentaconthect-



carbon atoms make 4 chemical bonds.
carbon atoms can be linked to each other by one
pair of electrons (single bond), two pair (double
bond), or three pair (triple bond).
the presence of double or triple bonds on the
carbon chain changes the chemical family.

alkanes
 all carbons are connected by single bonds
 the suffix –ane is added to the name of the compound
 the general formula is CnH2n+2
hexane

alkenes
 the carbon chain contains at least one double bond
 the suffix –ene is added to the name of the compound
 the general formula is CnH2n
propene

alkynes
 the carbon chain contains at least one triple bond
 the suffix –yne is added to the name of the compound
 the general formula is CnH2n-2
propyne



is defined as the structure associated with a
chemical formula.
for many organic compounds it is possible to
have more than one isomer for a given formula.
the simplest isomers are alkenes and alkynes
where the double or triple bond can have more
than one location:

1-butene

2-butene

number the carbons from the end closest to the
multiple bond:


1- hexene
the double bond is located closest to the lefthand side, so that is where numbering starts.


2-hexene
the double bond is closer to the right-hand side,
so numbering begins there.

1-hexene

1-hexene

these two are the same molecule.

1-butyne

2-butyne



hydrocarbon chains
halogens
alcohols

Hydrocarbon chains are carbon chains attached
to the main chain:
this is called
methylbutane




Prefixes are used to indicate the number of
carbons in the chain:
1 carbon - methyl2 carbons - ethyl3 carbons - propyl-

when it is possible to attach the hydrocarbon in
more than 1 place numbering is used:

2-methylpentane

3-methylpentane

4-methyl-2-pentene

2,3-dimethylpentane

3,4-dimethyl-2-pentene

2,4-dimethyl-3-ethylpentane

Halogens - group 17 elements attached to the
carbon chain:

1-fluoro-3-chloropentane

1-fluoro-1,1-diiodo-5,5,5-trichloro2-pentyne

Alcohols - are formed when –OH groups are
attached to the main chain:

1-pentanol

2-penten-1-ol

cyclopropane

cyclohexane

cyclohexene

2-chloro-4-fluorocyclohexene

benzene

benzene

phenol

toluene

dichlorobenzene

ortho-
meta-
para-

Complete organic nomenclature assignment

Quantum mechanics is a
mathematical treatment
into which both the wave
and particle nature of
matter could be
incorporated.


since the electron is both a
wave and a particle it is
impossible to give it’s location
or speed with certainty.
gives a probability density
map of where an electron has
a certain statistical likelihood
of being at any given instant in
time.


The probability map reveals the atomic
orbitals, and their corresponding energies.
An orbital is described by a set of three
quantum numbers.



This relates to the energy of the electron
As n becomes larger, the atom becomes larger
and the electron is further from the nucleus.
This is directly related to the period of the
atom on the Periodic Table




This quantum number depends on the value of n.
The values of l begin at 0 and increase to n – 1.
Value of l
0
1
2
3
Type of orbital
s
p
d
f
Theoretical g, h, i, etc. orbitals exist, but no
atoms have been created to use them.
This quantum number defines the shape of the
orbital.



This quantum number depends on l.
The magnetic quantum number has integer
values between –l and +l.
Magnetic quantum numbers give the threedimensional orientation of each orbital.



Value of l = 0.
Spherical in shape.
Radius of sphere
increases with increasing
value of n.


Value of l = 1.
Have two lobes with a node between them.


Value of l is 2.
Four of the five
orbitals have 4
lobes; the other
resembles a p
orbital with a
doughnut
around the
center.



electrons have spin,
which creates a magnetic
field
there are two spin states
possible, +1/2 and -1/2
a single orbital can hold a
maximum of two
electrons, which must
have opposite spin.


No two electrons in the
same atom can have
exactly the same energy.
For example, no two
electrons in the same atom
can have identical sets of
quantum numbers.

thus every electron location is defined in terms of
4 things:
a) Principal Quantum Number - 1 to 7
b) Angular Quantum Number – s, p, d or f
c) Magnetic Quantum Number – implied by number of
electrons in each shape; s has 2, p has 6, d has 10 and
f has 14
d) Spin Quantum Number – why each orbital can
contain 2 electrons

Electrons tend to occupy the lowest available orbital.
 The simplest atom, hydrogen has 1 electron.
 In its’ lowest, or ground state, this electron will occupy the
1s orbital, the lowest energy orbital available (see chart,
page 105)
 The next element, helium, has two electrons, both of
which will occupy the 1s orbital.
 Element three, lithium, has three electrons. The first two
will fill the 1s orbital while the third must move up to the
next energy level, 2s.

Thus the electron configuration of an atom is the
arrangement of the electrons from the lowest energy
level to the highest.



Consist of
 Number denoting the energy level.
 Letter denoting the type of orbital.
 Superscript denoting the number of electrons in
those orbitals.
For instance:
 Iron (Fe) – contains 26 electrons
 1s22s22p63s23p64s23d6
watch the order of filling
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Potassium - 19 electrons
 1s22s22p63s23p64s1
Silver - 47 electrons
 1s22s22p63s23p64s23d104p65s24d9
Tungsten - 74 electrons
 1s22s22p63s23p64s23d104p65s24d105p66s24f145d4
Plutonium - 94 electrons
 1s22s22p63s23p64s23d104p65s24d105p66s24f145d10
6p67s25f6
Write the correct electron configuration for the
following:
 Si, S, P, Ca, As, Fe, Br, Kr, At, U, Na1+, F1-, Ne
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- 14 e1- 1s22s22p63s13p3
- 16 e1- 1s22s22p63s23p4
- 15 e1- 1s22s22p63s23p3
- 20 e1- 1s22s22p63s23p64s14p1
- 33 e1- 1s22s22p63s23p64s23d104p3
- 26 e1- 1s22s22p63s23p64s23d6
- 35 e1- 1s22s22p63s23p64s23d104p5
- 36 e1- 1s22s22p63s23p64s23d104p6
- 85 e1- 1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p5
- 92 e11s22s22p63s23p64s23d104p65s24d105p66s24f145d106p67s25f4
Na1+ - 10 e1- 1s22s22p6
F1- - 10 e1- 1s22s22p6
Ne - 10 e1- 1s22s22p6
Si
S
P
Ca
As
Fe
Br
Kr
At
U
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promotion of an outer ‘s’ electron to the adjacent
‘p’ orbital.
turns non-bonding electrons into bonding
electrons
allows atoms to make more chemical bonds and
achieve a lower energy
applies to elements from groups 2, 13 and 14 only
for these elements promotion is the rule
Element
Unhybridized
Hybridized
beryllium
1s22s2
1s22s12p1
boron
1s22s22p1
1s22s12p2
carbon
1s22s22p2
1s22s12p3
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
are another way to illustrate the position of electrons.
They are best learned by comparison with electron
configuration:

Na (11 protons, 11 electrons)
electron configuration:
1s22s22p63s1

orbital diagram:

1s
2s
↑↓
↑↓
2p
↑↓ ↑↓ ↑↓
3s
↑
Group
Representative
Element
Electron configuration
Orbital Diagram
1
lithium
1s22s1
1s
↑↓
2s
↑
2
beryllium
1s22s12p1
↑↓
↑
↑
13
boron
1s22s12p2
↑↓
↑
↑ ↑
14
carbon
1s22s12p3
↑↓
↑
↑ ↑ ↑
15
nitrogen
1s22s22p3
↑↓
↑↓
↑ ↑ ↑
16
oxygen
1s22s22p4
↑↓
↑↓
↑↓ ↑ ↑
17
fluorine
1s22s22p5
↑↓
↑↓
↑↓ ↑↓ ↑
18
neon
1s22s22p6
↑↓
↑↓
↑↓ ↑↓ ↑↓
Repeat the last assignment, giving the orbital diagrams for the elements.
2p

Na1+, F1-, Ne are all the same:
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gives information only concerning the valence electrons.
Valence electrons are the electrons on the outside of an
atom; they are the electrons responsible for bonding and are
also the electrons gained or lost when an atom ionizes.
Valence electrons are electrons in the s and p orbitals of the
highest energy level reached by the electrons of an atom.
In this class when valence electrons are mentioned, the only
elements concerned are those in groups 1, 2, and 13 through
18.

group 1

group 2

group 13

group 14
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group 15

group 16

group 17

group 18
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Repeat last assignment, making lewis diagrams.
Fe and U have no lewis diagrams

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both give information about valence electrons.
if valence electrons are paired, they cannot be
used for bonding with other atoms. They are
lone-pair electrons.
unpaired valence electrons are bonding
electrons.
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5 valence electrons
1 lone pair
3 bonding electrons; this atom makes 3 chemical
bonds.
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4 valence electrons
0 lone pair
4 bonding electrons; this atom makes 4 chemical
bonds
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7 valence electrons
3 lone pair
1 bonding electrons; this atom makes 1 chemical
bond
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8 valence electrons
4 lone pair
0 bonding electrons; this atom makes 0 chemical
bonds
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Each box represents one
orbital.
Half-arrows represent the
electrons.
The direction of the arrow represents the spin of
the electron.
Pauli Exclusion Principle – no two electrons in
the same orbital can have the same spin
“For degenerate
orbitals, the lowest
energy is attained
when the number of
electrons with the
same spin is
maximized.”