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## PowerPoint Slideshow about ' Lewis Dot Structures' - lily

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

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

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.

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

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

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

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

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

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

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

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

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

H2O

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

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.

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

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

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

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

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

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.

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!

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!

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

*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.

*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.

CO2

CO2

C = 4v.e. x 1 = 4

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

Total v.e. available 16

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

CO2

C

O

O

Central atom

Total v.e.

16

O

C

O

Total v.e.

16

-4

12

remain

O

C

O

or

..

..

O

C

O

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

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

Total v.e.

16

12

remain

O

C

O

2

2

C has 4 and needs 4 more

*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.

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.

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.

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.

*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.

*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.

*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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