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Compounds and BondingCompounds and Bonding
Putting 2 and 2 TogetherPutting 2 and 2 Together
CovalentBonds
Sowhatarecovalentbonds?
Covalent Bonding: Sharing electrons
Cl2
Chlorineforms
acovalent
bondwith
itself
ClClHowwilltwochlorineatomsreact?
ClClEach chlorine atom wants to gain one electron to achieve an octet
ClClNeither atom will give up an electron –chlorine is highly electronegative.
What’s the solution – what can theydo to achieve an octet?
ClCl
Cl Cl
Cl Cl
ClCl
ClCloctet
ClCl
circle the electrons foreach atom that completestheir octets
octet
ClCl
circle the electrons foreach atom that completestheir octets
The octet is achieved byeach atom sharing theelectron pair in the middle
ClCl
circle the electrons foreach atom that completestheir octets
The octet is achieved byeach atom sharing theelectron pair in the middle
ClCl
circle the electrons foreach atom that completestheir octets
This is the bonding pair
ClCl
circle the electrons foreach atom that completestheir octets
It is a single bonding pair
ClCl
circle the electrons foreach atom that completestheir octets
It is called a SINGLE BOND
Cl Cl
circle the electrons foreach atom that completestheir octets
Single bonds are abbreviatedwith a dash
Cl Cl
circle the electrons foreach atom that completestheir octets
This is the chlorine molecule,
Cl2
O2
Oxygen is also one of the diatomic molecules
How will two oxygen atoms bond?
OO
OOEach atom has two unpaired electrons
OO
OO
OO
OO
OO
OO
Oxygen atoms are highly electronegative.
So both atoms want to gain two electrons.
OO
Oxygen atoms are highly electronegative.
So both atoms want to gain two electrons.
OO
OO
OO
OO
OO
OOBoth electron pairs are shared.
6 valence electronsplus 2 shared electrons
= full octet
OO
6 valence electronsplus 2 shared electrons
= full octet
OO
two bonding pairs,
OOmaking a double bond
OO =For convenience, the double bond
can be shown as two dashes.
OO
OO =This is the oxygen molecule,
O2this is so cool!!
• When two pairs of electrons are shared it is called a double bond.
H H \ / C C / \ H H
• When three pairs of electrons are shared it is called a triple bond.
H-C C-H
• When two pairs of electrons are shared it is called a double bond.
H H \ / C C / \ H H
• When three pairs of electrons are shared it is called a triple bond.
H-C C-H
Ionic Bonding
• Ionic Bonds
– Ionic bonding occurs when one atom transfers an electron to another atom
•This occurs when a metal reacts with a nonmetal
• Ionic Bonds
– Ionic bonding occurs when one atom transfers an electron to another atom
•This occurs when a metal reacts with a nonmetal
Na+1 + Cl-1 ® NaCl (table salt)
• Two rules for keeping track of electrons in ionic bonding reactions.
–Ions are formed when atoms gain or lose electrons to achieve a noble gas configuration (octet rule)
–The number of electrons that are lost must equal the number of electrons that are gained.
• Two rules for keeping track of electrons in ionic bonding reactions.
–Ions are formed when atoms gain or lose electrons to achieve a noble gas configuration (octet rule)
–The number of electrons that are lost must equal the number of electrons that are gained.
– Ionic Compounds
– Compounds that are held together by ionic bonds are called ionic compounds.• The elements in Group IA and IIA tend to lose
electrons for form positive ions (Cations)
• The elements in Group VIA and VIIA tend to gain electrons to form negative ions. (Anions)
– Ionic Compounds
– Compounds that are held together by ionic bonds are called ionic compounds.• The elements in Group IA and IIA tend to lose
electrons for form positive ions (Cations)
• The elements in Group VIA and VIIA tend to gain electrons to form negative ions. (Anions)
N O Cl
N3-
nitride ionO2-
oxide ionCl-
chloride ion
Example of anions
Some examples of Cations:
Na Sr Ba
Na+
sodium ionSr2+
strontium ionBa2+
barium ion
IONICBONDING
In an IONIC bond,electrons are lost or gained,resulting in the formation of IONSin ionic compounds.
FK
FK
FK
FK
FK
FK
FK
FK+ _
FK+ _
The compound potassium fluorideconsists of potassium (K+) ions
and fluoride (F-) ions
FK+ _
The ionic bond is the attractionbetween the positive K+ ion
and the negative F- ion
