Bonding Part II Covalent

7/30/2019 Bonding Part II Covalent

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PART II


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Covalent

Bonds


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LETS

FIRST

REVIEW

IONIC

BONDING


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In an IONIC bond,

electrons are lost or gained,

resulting in the formation ofIONS

in ionic compounds.

FK


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FK


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FK


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FK


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FK


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FK


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FK


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FK+ _


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FK +_

The compound potassium fluoride

consists of potassium (K+) ions

and fluoride (F-) ions


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FK +_

The ionic bond is the attraction

between the positive K+ ion

and the negative F- ion


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So

whatare

covalent

bonds?


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In covalent bonding,

atoms still want to achievea noble gas configuration

(the octet rule).


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atoms still want to achieve

a noble gas configuration(the octet rule).

But rather than losing or gaining

electrons,atoms now share an electron pair.


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atoms still want to achieve

a noble gas configuration(the octet rule).

But rather than losing or gaining

electrons,

atoms now share an electron pair.

The shared electron pairis called a bonding pair


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Cl2

Chlorine

formsa

covalent

bondwith

itself


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ClClHow

willtwo

chlorine

atomsreact?


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ClClEach chlorine atom wants togain one electron to achieve an octet


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ClClNeither atom will give up an electron

chlorine is highly electronegative.

Whats the solutionwhat can they

do to achieve an octet?


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ClCl


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Cl Cl


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Cl Cl


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Cl Cl


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Cl Cloctet


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Cl Cl

circle the electrons for

each atom that completes

their octets

octet


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Cl Cl



their octets

The octet is achieved by

each atom sharing the

electron pair in the middle


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Cl Cl



their octets

The octet is achieved by

each atom sharing the

electron pair in the middle


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Cl Cl



their octets

This is the bonding pair


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Cl Cl



their octets

It is a single bonding pair


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Cl Cl



their octets

It is called aSINGLE BOND


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Cl Cl



their octets

Single bonds are abbreviated

with a dash


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Cl Cl



their octets

This is the chlorine molecule,

Cl2


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O2Oxygen is also one of the diatomic molecules


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How will two oxygen atoms bond?

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OOEach atom has two unpaired electrons


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OO


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OO


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OO


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OO


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OO


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OO


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Oxygen atoms are highly electronegative.

So both atoms want to gain two electrons.

OO


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Oxygen atoms are highly electronegative.

So both atoms want to gain two electrons.

OO


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OO


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OO


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OO


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OO


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OOBoth electron pairs are shared.


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6 valence electrons

plus 2 shared electrons

= full octet

OO


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6 valence electrons

plus 2 shared electrons

= full octet

OO


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two bonding pairs,

OO

making adoublebond


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OO=For convenience, the double bond

can be shown as two dashes.

OO


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OO=This is the oxygen molecule,

O2thisis so

cool!

!


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Covalent bonding allows for

an amazingly large varietyof compounds such as


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small compounds like

water and carbon dioxide,


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and ethanol (alcohol),

l d


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to larger compounds

such as aspirin,

(21 atoms)

and the


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and the

sex hormones

estradiol(estrogen)

and

testosterone,

(49 atoms)

(44 atoms)


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to all of the 40,000 proteins

you have in your body,

including

insulin


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insulin,with 779 atoms,

d hemoglobin


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and hemoglobin,with about 11,000 atoms!


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There are an estimated

1040 possible compoundscontaining up to 50 atoms

The known chemical world,including natural and

synthetic compounds,

is far far far below 1% of that.

NATURE volume 442 p. 502 3 August 2006


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As of 2007, there are about

31,000,000 known compounds;

About 12.5 million of those

are commercially available.

Thousands of new compounds

are discovered or synthesizedevery week!

Bonding Part II Covalent

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