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Lewis Dot Structures. Gilbert Lewis One of Americas most influential Chemist . Lewis Dot Structures. Gilbert Lewis One of Americas most influential Chemist .

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Lewis Dot Structures

Gilbert Lewis

One of Americas most influential Chemist.


Lewis Dot Structures

Gilbert Lewis

One of Americas most influential Chemist.


He was the first person to speak of electrons being shared rather then transferred. His was the first description of covalent bonding.


Lewis dot structures help us to understand the shape and structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs


Step 1 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Identify what element are in the formula and how many valence electrons each one contributes to bonding.


Step 1 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Identify what element are in the formula and how many valence electrons each one contributes to bonding.

H2O


Step 1 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Identify what element are in the formula and how many valence electrons each one contributes to bonding.

H2O

H = 1v.e. x 2 = 2

O = 6v.e. x 1 = + 6

Total v.e. available 8


Step 2 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Identify the central atom. Most formulas are written with the central atom first.

The lowest electronegative atom tends to be the central atom.

H is never the central atom.


Step 2 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Identify the central atom. Most formulas are written with the central atom first. The lowest electronegative atom tends to be the central atom. H is not ever the central atom.

H2O


Step 2 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Identify the central atom. Most formulas are written with the central atom first. The lowest electronegative atom tends to be the central atom. H is not ever the central atom.

H2O

O

H

H

Central atom


Step 3 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Draw a single line between the atoms which signify two shared electrons. Each bond removes two v.e. from the amount you started with.


Step 3 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Draw a single line between the atoms which signify two shared electrons. Each bond removes two v.e. from the amount you started with.

Total v.e.

8

H

O

H


Step 3 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Draw a single line between the atoms which signify two shared electrons. Each bond removes two v.e. from the amount you started with.

Total v.e.

8

-4

4

remain

H

O

H

or

..

..

H

O

H


Step 4 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Count and see how many electrons you still need to fulfill the octet rule for each element. Compare this number to how many electrons you have available.


Step 4 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Count and see how many electrons you still need to fulfill the octet rule. Compare this number to how many electrons you have available.

Total v.e.

8

4

remain

H

O

H

H has 2 and only needs 2

It’s good!


Step 4 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Count and see how many electrons you still need to fulfill the octet rule for each element. Compare this number to how many electrons you have available.

Total v.e.

8

4

remain

H

O

H

2

H has 2 and only needs 2

It’s good!


Step 4 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Count and see how many electrons you still need to fulfill the octet rule for each element. Compare this number to how many electrons you have available.

Total v.e.

8

4

remain

H

O

H

2

2

O has 4 and needs 8 so it needs 4 more


Step 5 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

*If you have enough electrons left just add them to each element in electron lone pairs.

*If you don’t have enough electrons you must share more electrons by forming additional bonds.

*If you have too many electrons place them on the central atom.


Step 5 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

*If you have enough electrons left just add them to each element in electron lone pairs.

..

Total v.e.

4

-4

0

remain

H

O

H

..

Both H’s have 2 and O has 8 they all have full octets with no left over electrons.


Step 1 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Identify what element are in the formula and how many valence electrons each one contributes to bonding.

CO2


Step 1 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Identify what element are in the formula and how many valence electrons each one contributes to bonding.

CO2

C = 4v.e. x 1 = 4

O = 6v.e. x 2 = + 12

Total v.e. available 16


Step 2 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Identify the central atom. Most formulas are written with the central atom first. The lowest electronegative atom tends to be the central atom. H is not ever the central atom.

CO2


Step 2 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Identify the central atom. Most formulas are written with the central atom first. The lowest electronegative atom tends to be the central atom. H is not ever the central atom.

CO2

C

O

O

Central atom


Step 3 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Draw a single line between the atoms which signify two shared electrons. Each bond removes two v.e. from the amount you started with.

Total v.e.

16

O

C

O


Step 3 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Draw a single line between the atoms which signify two shared electrons. Each bond removes two v.e. from the amount you started with.

Total v.e.

16

-4

12

remain

O

C

O

or

..

..

O

C

O


Step 4 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Count and see how many electrons you still need to fulfill the octet rule. Compare this number to how many electrons you have available.

Total v.e.

16

12

remain

O

C

O

O has 2 and needs 6 more


Step 4 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Count and see how many electrons you still need to fulfill the octet rule. Compare this number to how many electrons you have available.

Total v.e.

16

12

remain

O

C

O

2

O has 2 and needs 6 more


Step 4 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Count and see how many electrons you still need to fulfill the octet rule. Compare this number to how many electrons you have available.

Total v.e.

16

12

remain

O

C

O

2

2

C has 4 and needs 4 more


Step 5 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

*If you have enough electrons left just add them to each element in electron lone pairs.

*If you don’t have enough electrons you must share more electrons by forming additional bonds.

*If you have too many electrons place them on the central atom.


Step 5 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Count and see how many electrons you still need to fulfill the octet rule. Compare this number to how many electrons you have available.

Total v.e.

16

12

remain

O

C

O

2

2

4

Needs 6

Needs 4

Needs 6

You have 12 electrons left but you still need 16. You don’t have enough and must add more bonds.


Step 5 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Count and see how many electrons you still need to fulfill the octet rule. Compare this number to how many electrons you have available.

Total v.e.

16, 12

10

remain

O

C

O

4

2

6

Needs 4

Needs 2

Needs 6

You have 10 electrons left but you still need 12. You don’t have enough and must add more bonds.


Step 5 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

Count and see how many electrons you still need to fulfill the octet rule. Compare this number to how many electrons you have available.

Total v.e.

16, 12, 10

8

remain

O

C

O

4

4

8

Needs 4

Needs 0

Needs 4

You have 8 electrons left and you need 8. You have enough and do not need to add more bonds.


Step 5 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

*If you have enough electrons left just add them to each element in electron lone pairs.

*If you don’t have enough electrons you must share more electrons by forming additional bonds.

*If you have too many electrons place them on the central atom.


Step 5 structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

*If you have enough electrons left just add them to each element in electron lone pairs.

..

..

Total v.e.

8

-8

0

remain

O

C

..

O

..

All three atoms have 8 electrons and have full octets with no left over electrons.


Hints structure of atoms. Bonds represent a pair of shared electrons while excess electrons are show in lone pairs

*Always make sure the outside atoms have full octets. Place any odd electrons situations on the central atom.

*If you have a polyatomic cation subtract the positive charge from the starting # of valence electrons.

*If you have a polyatomic anion add the negative charge to the starting # of valence electrons


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