Covalent bonding
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Transcript of Covalent bonding
Covalent bonding
Grade 9 Chemistry
Starter
• What ions do Chlorine form?
• Imagine you have 2 chlorine ions – how could they help EACH OTHER to reach a stable state?
• It might help if you draw out the Lewis structures for 2 chlorine ions!
LET’SFIRSTREVIEWIONICBONDING
In an IONIC bond,electrons are lost or gained,resulting in the formation of IONS
in 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
Sowhatarecovalentbonds?
In covalent bonding,atoms still want to achievea noble gas configuration(the octet rule).
In covalent bonding,atoms still want to achievea noble gas configuration(the octet rule).
But rather than losing or gainingelectrons,atoms now share an electron pair.
In covalent bonding,atoms still want to achievea noble gas configuration(the octet rule).
But rather than losing or gainingelectrons,atoms now share an electron pair.
The shared electron pairis called a bonding pair
Cl2
Chlorineforms
acovalent
bondwithitself
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
Cl Cl
Cl Cloctet
Cl Cl
circle the electrons foreach atom that completestheir octets
octet
Cl Cl
circle the electrons foreach atom that completestheir octets
The octet is achieved byeach atom sharing theelectron pair in the middle
Cl Cl
circle the electrons foreach atom that completestheir octets
The octet is achieved byeach atom sharing theelectron pair in the middle
Cl Cl
circle the electrons foreach atom that completestheir octets
This is the bonding pair
Cl Cl
circle the electrons foreach atom that completestheir octets
It is a single bonding pair
Cl Cl
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
O2Oxygen 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!!
COVALENT BONDbond formed by the sharing of electrons
What is a covalent bond?
Atoms ___________ one or more electrons with each other to form the bond.
Each atom is left with a ________________ outer shell.
A covalent bond forms between two _________________.
Example 1: Hydrogen + Hydrogen Example 2: Hydrogen + Oxygen
SHARE
COMPLETE
NONMETALS
1. Dot and cross diagram2. Formula
Covalent Bond
• Between nonmetallic elements of similar electronegativity.
• Formed by sharing electron pairs• They are not conductors at any state• Examples; O2, CO2, C2H6, H2O, SiC
Now try the covalent bonding practice sheet