Summary Chemical bonding

chemical tracking
ionic bonds = formed when electrons are transferred from one atom -10 another
what are ionic bonds? ④ ectrostatic forces of attraction = exists between ions of Opposite charges

- electrostatic force of attraction? metals + non -
metals




what are covalent bonds? =
formed by sharing of electrons between Z91-0MS

-




valence electrons not used in bonding? ① nonbinding electrons formation of an
"


Thrive pairs
:
-
=
E- molecule
② ione pairs ÷ 3iOM Pairs
bonding pair
.




what are non-polar covalent bonds =
occurs between atoms that share electrons equally
* electronegativity.es
differ by < 0.5

EQUALLY shared electrons M :X

what are polar covalent bonds =
electrons are shared but not equally shared * electronegativity.es
differ by 05 -2.0
M5-1XS
-



UNEQUALLY shared electrons

what are ionic bonds =
between anetaiandanon metal and involves ions -
*
electronegativity.es
differ by > 2.0
ELECTROSTATIC FORCES OF ATTRACTION Mt
-


X


definition of electronegativity =
the ability of a chemically bondedatominacompound-odrawsharedelec-rons.TO
itself
- electronegativity trend ↑ ↓
electronegativity =
tendency -10 lose electrons

electronegativity ↓ down the group as metallic characteristic

electronegativity ↑ across a period
/ decreases
definition of electron affinity =
an isolated atom 's ability -10 attract an additional electron in gaseous state




dipole moment an arrow indicating the direction of electron shift in polar covalent molecule



octet rule =
atoms will lose , gain , or share electrons in order -10 achieve a noble gas

configuration
=
are presentation of covalent bonding
explain lewis structure
- single bond
single bond = held together by one electron pair :P
.


_yC=Ñ :




double bond -_
Share two pairs of electrons 2 Shared pairs

- double bond :


- triple bond
element number of bonds % = most common


number of bonds formed by some H I % =
rare

C 4 By
non-metals N
3 =
common


3 4

0 2 I 3

F I

ce 'brI I > I


formal charge =
tveappavent electronic charge ofeachatomina molecule
formal charges =
valence e- -

associated e-
*
adding all the formal charges of -1M atoms must be equal -10 the overall charge
on the molecule ion


guidelines to determine the best *

*
alewis structure where all formal charges are zero is preferred

small formal charges are preferred .to large formal charges
possible lewis structure * formal charges should be consistent with electroregativities
① central atom has fewer than eight electrons are -109 Shortage of electrons
exceptions to the octet rule ② central atom has fewer than eight electrons are -10 Odd number of electrons

③ central atom has more than eight electrons

, when the central atom has fewer e.g. t.be ,Ñ,He small atoms cannot accommodate -101-00 many electron

than eight electrons due to shortage
H~oniy4-otalvalenceeiec-ronsin-vesystemfreeradic.ie
H -

be -




of electrons
-_
not stable ,
it usually exists as an intermediate during areaction

When drawing lewisstruc-nrewithoddnumberofelectrons.tk central
when the central atom has fewer
than eight electrons due to an odd atomwil havetveoddnumberofelec-ronstherearen-vaie.nu
number of electrons j :/
electrons intnesystem
:j=N -



.




for elements that are in period } and below

when the central atom has more than because they have dorbitalsthatcanbeuseain bonding

eight electrons :
: .



i.F.
.




=
electrons repel one another
basis of the VSEPR model
domain __
regionofspacearound-vea-omwhe.ve the electrons are found
Ñ
=C=O I H
. .
- -
H
ione pairs and bond pairs f. =p
: -
:

.
,
H
- electron pairs 2 double bonds 1 single bond 3 single bonds

ldonblebond live pair

liorepair

electron pair geometry = electron pair geometry -_
arrangement of electron pairs

molecular geometry = molecular geometry __
arrangement of bonded atoms


① molecules inwhichtvecentralatomnasnoiovepair
two categories of molecules ② molecules with
acentrala-om-hatnasoveormoreiovepairctassofmolec.mil
examples lewis structure
electron pair
geometry angle
geometry of molecules and ions where b) ecez . .




ie
AB2 :C ? be :


central atom has no lone pairs
- -



valence e- . "



=/ 6 linear 180°
BE }
AB3 trigonal
valence e-
=
24
;jj :

Planar 1200
: -
B- É :

r -




CH4
H
AB4 valence e-
'
=s
H -
C -
H tetrahedral 109.5°
,
H


PC15 ' '




ill
:

AB5 valence e-
trigonal 120°
. .




:( e
'




=40 Ce :
-
p -




bipyramidalqoo.ie \ ::
- .


/
Cf :
:




SF6
AB6 valence e- : :



=48 Octahedral 90°
:É
/
I 'É :


:[
' - : . .




① between bonding pairslbpvsbp )
three types of repulsive forces ② between lorepairsllpvsl.pl

③ between bonding pairs and / One pairs ILPVSPSP)
VSEPR repulsive forces arranged in * lorepairs-akeupmorespaoe-hanbondedpai.rs
strongest to weakest LPVSLP > LPVSIBP > BPVSBP
'