CHEM 121
Semester 1
September
2024
,Chem 121 -
unit 1 :
intro
Structure of atom - all matter is chemical
protons
↳~lamu
nucleus
↳ (+) charge pt
↳
defines element
·n
neutrons
-
↳
a
~lamu
= 100 000
Va
,
↳
neutral/no charge no
~
electrons
↳
~0 amu
↳
1-1 charge e
Atomic Notation Isotopes /variation of neutron # of element
mass # element
(p
+
+ n% symb
If
13
22C
eg
.
C
6 pt 6 pt
6 no 7n0
atomic 98 .
93 % 1 . 07 % natural abundance
↓
Average weight of elements
Aw =
( M , 2c)( % 12c) +
(misc)( % 13c)
=
12 . Oll amu
Chem & Lewis
121- unit 2 :
chemical bonding structures
Compounds +Chem combo of 2 +
elements
Covalent vs . Ionic bonds
covalent+ sharing e-cheld w/ attraction
↳
polar covalent bond +A in electronegativity) than non-polar but < ionic
>
-
e- towards I
polarized atom
be isolable ?
-
eg. How many species can
↑
-
e-shared 10e
unequally no charge
possible
↳ + -
OF4
F not
-
non-polar covalent bond shared equally H2Te
Fz H -
Te -
H
2
"
lonic ->
stealing e-Cheld w/ electrostatic force
NaBra
(F-j) E
Co
↳
11/14)
[Na]* (Br] -
:
ions species wi overall charge [Br]
⑦
Location : # banion :
1- · co = 0 FC :
↳
isoable :
ability to be isolated of 2
* neutral atoms
↳
cations not iscable wout to balance diff elements
anions charge cannot be
* no FC A i soelectronic A
for
Electronegativity + tendency atom to attract e-
NM
)4 diff
M ~
Ionic Compound
:
stolen in electronegativity = Salt
low
high (raxrnx)
covalent compound : NM + NM u
Sharing
high high
↓
Bond Dipoles
, Bond dipoles -*
polar covalent bonds Represents
of e- >
unequal sharing partial charge
·
=
more electro negitive
eg
Yg- polarity electronegativity
·
=
A
.
St in
C
a
=
(t)
NOTE :
↳ >
Free Radical -
unpaire-creating unstable molec .
↳
-sheilding >
-
e-behaviour depends on Radius as well (strength of pt pull e in but too many e = ↓
strength)
Electrons bond in order to fill octet : Ovalence e-
(expanded/hyper valent)
Bond order
>
-
# bond pair between atoms/#bond groups egi
la
·
Bond length + distance between 2 nuclei
↓ ↓
forCo-
bond order a attraction) . lowest
eg bond dissociation
energy
as
stronger
"(-c
a) CH02-
dissociation - needed to break bond b) CH2S
Bond energy energy
↳↑
bond order & (more bonds/stronger to break) c) co
· a
as
0 = c = 0:
d) CO2
>
Formal Charge shared e-carried
equally Oxidation charge of assigned to
-
state - atom when e more
Fc =
e- brought
-
e-carried electro negitive
H H
H
!o .
H representative of
-
Partial Charge most actual
,
charge distribution
*
#
me a
polar
Lewis Structures
+
1.
arrange atoms /least electronegative central eg
. [NO2]
.
2 valence e
+
.
3
4.
Single bond
for cation/anion
(:0 =
x
=
0)
adjust
5
. form additional bonds w/ unpaired e-
6. for octets
rearrange
.
7
FC
.
8 check:
* HYPERVALENCED > (not
e-then octet terminal atoms
-
more on
↳ ONLY occurs if FC
↳
P ,
C1 ,
I
-
ResonanceStructure diff e-arrangement
L
BEST -
Minimal FC & FC on more electronegative
↳
chemically resonable FC 8 typical bonding
-
small
>
Isomer structure diff arrangement
-
atom
Semester 1
September
2024
,Chem 121 -
unit 1 :
intro
Structure of atom - all matter is chemical
protons
↳~lamu
nucleus
↳ (+) charge pt
↳
defines element
·n
neutrons
-
↳
a
~lamu
= 100 000
Va
,
↳
neutral/no charge no
~
electrons
↳
~0 amu
↳
1-1 charge e
Atomic Notation Isotopes /variation of neutron # of element
mass # element
(p
+
+ n% symb
If
13
22C
eg
.
C
6 pt 6 pt
6 no 7n0
atomic 98 .
93 % 1 . 07 % natural abundance
↓
Average weight of elements
Aw =
( M , 2c)( % 12c) +
(misc)( % 13c)
=
12 . Oll amu
Chem & Lewis
121- unit 2 :
chemical bonding structures
Compounds +Chem combo of 2 +
elements
Covalent vs . Ionic bonds
covalent+ sharing e-cheld w/ attraction
↳
polar covalent bond +A in electronegativity) than non-polar but < ionic
>
-
e- towards I
polarized atom
be isolable ?
-
eg. How many species can
↑
-
e-shared 10e
unequally no charge
possible
↳ + -
OF4
F not
-
non-polar covalent bond shared equally H2Te
Fz H -
Te -
H
2
"
lonic ->
stealing e-Cheld w/ electrostatic force
NaBra
(F-j) E
Co
↳
11/14)
[Na]* (Br] -
:
ions species wi overall charge [Br]
⑦
Location : # banion :
1- · co = 0 FC :
↳
isoable :
ability to be isolated of 2
* neutral atoms
↳
cations not iscable wout to balance diff elements
anions charge cannot be
* no FC A i soelectronic A
for
Electronegativity + tendency atom to attract e-
NM
)4 diff
M ~
Ionic Compound
:
stolen in electronegativity = Salt
low
high (raxrnx)
covalent compound : NM + NM u
Sharing
high high
↓
Bond Dipoles
, Bond dipoles -*
polar covalent bonds Represents
of e- >
unequal sharing partial charge
·
=
more electro negitive
eg
Yg- polarity electronegativity
·
=
A
.
St in
C
a
=
(t)
NOTE :
↳ >
Free Radical -
unpaire-creating unstable molec .
↳
-sheilding >
-
e-behaviour depends on Radius as well (strength of pt pull e in but too many e = ↓
strength)
Electrons bond in order to fill octet : Ovalence e-
(expanded/hyper valent)
Bond order
>
-
# bond pair between atoms/#bond groups egi
la
·
Bond length + distance between 2 nuclei
↓ ↓
forCo-
bond order a attraction) . lowest
eg bond dissociation
energy
as
stronger
"(-c
a) CH02-
dissociation - needed to break bond b) CH2S
Bond energy energy
↳↑
bond order & (more bonds/stronger to break) c) co
· a
as
0 = c = 0:
d) CO2
>
Formal Charge shared e-carried
equally Oxidation charge of assigned to
-
state - atom when e more
Fc =
e- brought
-
e-carried electro negitive
H H
H
!o .
H representative of
-
Partial Charge most actual
,
charge distribution
*
#
me a
polar
Lewis Structures
+
1.
arrange atoms /least electronegative central eg
. [NO2]
.
2 valence e
+
.
3
4.
Single bond
for cation/anion
(:0 =
x
=
0)
adjust
5
. form additional bonds w/ unpaired e-
6. for octets
rearrange
.
7
FC
.
8 check:
* HYPERVALENCED > (not
e-then octet terminal atoms
-
more on
↳ ONLY occurs if FC
↳
P ,
C1 ,
I
-
ResonanceStructure diff e-arrangement
L
BEST -
Minimal FC & FC on more electronegative
↳
chemically resonable FC 8 typical bonding
-
small
>
Isomer structure diff arrangement
-
atom
