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Chemistry 20 AP Notes
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Chemistry 20 AP notes including bonding, gases, solutions, and stoichiometry. Handwritten notes with diagrams and practice problems. Final class grade was 93%.
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unit one; bondingHydrates 06 02 24
.
.
-
lonk compounds that have a certain number of water molecules in their formula
4) CuNO , · GH , O + copper (1) nexahydrate
4)
CasOe o
SH20 >
-
calcium sulfate pentahydrate
Atoms 12 02
.
.
24
-
atomic number is the number of protons in an atom
-
electrically neutral means protons (p+) =
electrons (e)
form compounds in an effort to complete valence shell (octet rule)
-
atoms gain a
Electron Dot Diagram
-
show only valence e, all other shells are full and don't participate in bonding
e ' individually
place for the first ? then pair up as each other and will remain alone if possible
necessary ; e- repel
-
-
bonding occurs with unpaired electrons
Forming Bonds
-
cations and anions form an lonk band I' are transferred to the anion resulting in an loni solid
, ,
-
typically two non-metals form a covalent wond , e are shared
-
bonds result from attraction of nucles for electrons (electroneganvin)
↳ e
9
Na ici
-
t
. .
- -
-
-
Cl .. > sodium chloride
-
Na ~
..
-
[ F )
"
:
... F :
-
,
:
-
ca +
ca] calcium fivoricle
-
> 7
3.
Fi 1 F ]
: :
+
(Mg)"
I
u9in :
"
( N ) : :
·
magnesium nitricle
lMg !
Mig .
( N )
: :
:
+
(Mg)"
"
Nig
lonk
Bonding and Crystal Lattices
-
once an 101 forms
,
each cation attracts any nearby anions
-
for NaCl each con attracts 6 long of opposite charge
,
4 all attractive forces are equal ,
so no specific pairs of sodium and chlorine could be labelled as a molecule
4 formula Nacl implies the 2 lons form a 3D crystal lattice with a 1 : 1 ratic
4 Nacl is a formula unit, not a molecule
-
strong attraction in 3D lattices is what makes all lonk compounds solids at room temperature
4 high melting point as lots of energy is required to overcome strong electrostatic forces
metal character
-
metals are good electrical conductors because electrons in the electron sea are free to flow and carry electrical current
-
malleable ductle because local bonds can easily be broken and reformed
,
-
group trend : as you go down a group metallic character
,
increases because lonization energy decreases
-
period trend : as you go across a period (L to R) metallic character decreases because lonization energy increases
Metallic Bonds
-
form between delocalized electrons and positively charged Metallic lons
-
metals do not form bonds with other metals because of surface roughness ,
the atoms cannot get physically close enough
·
covalent Bonds
Oxygen difluoride
non-conductors all phases ↑ F
typically involves 2 or more non metals ; low melting/boiling point soft solids in
-
,
,
-
Most common is single wond ,
sharing of 1 pair of electrons between atoms
-
usually molecule furthest to left is written first H -... H H
P""I phosphorus trimydride
H
it
, BondingTerminology
pairs : formed when there are more than he in the valence shell
electron dot
diagram -electron
-
unpaired electrons : electrons that don't have a partner ,
form bonds with other atoms
pair : When two atoms share electrons and form covalent bond
[-ounding
a
Molecules
-
lone pair : electron pairs not involved in ronding
single wond : I shared pair of electrons
-
bond types
" -
-
double bond
triple wond
:
:
2
3
shared pairs
shared pairs
of
of
electrons
electrons
4) Bond Type Example Diagranis
CO :O : C :: O : double wond
HCN H -
:
C N :
single bund triple bond ,
Structural Formulae
-
show individual atoms in the molecule and the words between the atomo
-
each bonding pair is represented with a line
lone pairs are not shown
it
↑
H C H G
CHA
-
Hz g
-
4e g CO2 0 = c = 0
. .
I / &
H H H
HCN H -
C = N
Exceptions to the Octet Rule 13 82 24
. .
-
Goron (B) , hydrogen (H) ,
and hellum (He) have less ability to attract electrons to form a complete octet (8 electrons)
Expanded octets
-
atoms in periods 3-7 can bond with other atoms in such a way that they end up with more than 8 electrons in their octets
-
they are able to do this because of their d orbitals in the outer shells that can accept electrons
-
If you end up with an extra pair of electrons ,
this can be placed onto the central atom as a lone pair ,
as long as it's in the 3rd period or higher
Complex Lewis Dot Diagrams
1. count total valence electrons from all atoms .
If it is charged subtract or add the
corresponding electrons
,
with unpaired electrons the central atom(r) the other atoms around it
. Atoms
2 the most is .
Arrange
each pair of atoms to represent
. Draw one pair of
3 electrons between a
single rund
Fill octets for all until you run
.
4 atoms starting at the outside and then the central atomcs) out of electrons
electrons for the central atom ? More lone pairs to form
·
. Not enough double/triple words
Resonance structures
-
If there is more than one possible Lewis structure ,
the several possibilities are called resonance structures
-
Molecule/polyatomic
the On will flip back and forth between the different resonances
-
the electrons more out the atoms have not
- - , -
N N
& &
:% . .
0
i
:... O..
Bond order 20 . 02 23.
-
refers to the number of lands cringle double triple
, ,
·
due to resonance structures , an atom might have an effective bond order that isn't a whole number
total bonds
-effective number of Fonds/bond order :
central atom
atoms conded to
4) e .
. wond order
g for NOs
v
- - -
N 3 bonds
= 1 5 . effective bonds
& & 2 atoms
00 00
, complex Lewis Dot Diagrams with Bond order Practice
...
-- g
G
NO
, To
I : o
- o
= 1 .
5 effective bonds
- -
3
30 =/
3
effective Goed
-
-
2
~
2
- - -
2
--
0 G
=
2
5
-
< Y
ori-o. dro
effective bonds
-
Os 1 .
-
-
Ho
-
= I effective cond
Formal Charge
-
In some cases the atoms In a molecule can be arranged in different ways when drawing a Lewis Diagram
,
-
formal charges are calculated to identify the most stable/likely structure
the most stable structure the one which the formal closest to o
-
is in charges are
-
the sum of the formal charges on a neutral atom will be
polyatomic will be equal to the overall charge of the
-
the sum of formal charges on a lon ion
-
formal charge = valence e in an atom-clone e + number of bonds)
↳ e .
.
g · = c = :
0 = C- :
· = 0 =
S C 000000
valence 6 & 6 6 G 6 G &
lone bond 6 & 6 5 - 7 6 - 6
pair +
0 2 -
2
O 8 8 1 0.
formal charge
Bond Length and Bond Energy
~
triple bonds are shortest , then double then , single
rand the amount of energy required to make a chemical rond
-
energy is
bond energy harder bond to break
higher
-
=
-
shorter bonds have higher bond energy
Glucose Molecule (CH , 200)
!
H
H
......
H
" ↓
"
- &
% ::::.
"
:
:
0 :
it it it it if it
Molecular
↑
shapes 21 02 24
.
.
-
Stereochemistry :
studying the 3D shapes of molecules
-
VSERP (Valence Shell Electron Pair Repulsion) theory predicts the shape
4) e-pairs repel each other so they want to spread as far as possible around an atom
VSERP BASICS
-
lone pairs take up more space than a bonding pair
-
repulsion between2 lone pairs is the greatest
-
repulsion between I sanding pairs is the least
-
double bonds can be treated as
single bonds in terms of repulsion with other pairs
VSERP Symbols
- A represents central atoms
-
X represents any atom bonded to central atom
'E' represents a lone pair e on central atom
-
-
X + E represents the number of charge clouds surrounding the central atom
'
-
AXmE , where in is the number of bonded atoms and in is the number of love pairs on the central atom
normal/ backward
f l a t-
1111II/I
>
forward band
angle
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