remove

student.kc.school.nz

remove

Electronegativity


Ionic covalent continuum

• When chlorine and hydrogen react the

covalently bonded HCL is made

• When chlorine and sodium react ionicly

bonded NaCl is formed

• Why does Cl share electrons with H yet

remove electrons from Na?


Why does Cl share electrons with H

yet remove electrons from Na?

• Hydrogen holds its electrons really tightly in

H-H gas

• Sodium is a metal the doesn’t hold it’s

valance electrons as tightly

• Chemists use the term electronegativity


Electronegativity

What is it?

• Electronegativity is the power of an

atom to attract electron density

in a covalent bond

Remember the above definition …

Or in layman's terms

the “attractiveness” of an atom to

electrons in a bond


Electronegativity

Pauling’s electronegativity scale

• The higher the value, the more

electronegative the element

• Fluorine is the most electronegative element

• It has an electronegativity value of 4.0


Electronegativity

Pauling’s electronegativity scale


Electronegativity

Pauling’s electronegativity scale

F


Electronegativity

Pauling’s electronegativity scale

F

4.0


Electronegativity

Pauling’s electronegativity scale

Li

1.0

F

4.0


Electronegativity

Pauling’s electronegativity scale

Li

1.0

Be

1.5

F

4.0


Electronegativity

Pauling’s electronegativity scale

Li

1.0

Be

1.5

B

2.0

F

4.0


Electronegativity

Pauling’s electronegativity scale

Li

1.0

Be

1.5

B

2.0

C

2.5

F

4.0


Electronegativity

Pauling’s electronegativity scale

Li

1.0

Be

1.5

B

2.0

C

2.5

N

3.0

F

4.0


Electronegativity

Pauling’s electronegativity scale

Li

1.0

Be

1.5

B

2.0

C

2.5

N

3.0

O

3.5

F

4.0


Electronegativity

Pauling’s electronegativity scale

Li

1.0

Be

1.5

B

2.0

C

2.5

N

3.0

O

3.5

F

4.0

Na

0.9

Mg

1.2

Al

1.5

Si

1.8

P

2.1

S

2.5

Cl

3.0


Electronegativity

Pauling’s electronegativity scale

H

He

Li

1.0

Be

1.5

B

2.0

C

2.5

N

3.0

O

3.5

F

4.0

Ne

Na

0.9

Mg

1.2

Al

1.5

Si

1.8

P

2.1

S

2.5

Cl

3.0

Ar


Electronegativity

Pauling’s electronegativity scale

H

2.1

He

Li

1.0

Be

1.5

B

2.0

C

2.5

N

3.0

O

3.5

F

4.0

Ne

Na

0.9

Mg

1.2

Al

1.5

Si

1.8

P

2.1

S

2.5

Cl

3.0

Ar


Electronegativity

Pauling’s electronegativity scale

H

2.1

He

-

Li

1.0

Be

1.5

B

2.0

C

2.5

N

3.0

O

3.5

F

4.0

Ne

-

Na

0.9

Mg

1.2

Al

1.5

Si

1.8

P

2.1

S

2.5

Cl

3.0

Ar

-


So what does all this mean?

• Same atoms bonding

= same electronegativity

= pure covalent bond

• Different atoms bonding

=different electronegativity

= Polar covalent or Ionic bond

Confused? How do we tell which one?

Difference in electronegativity

Covalent and ionic are a opposite ends of the

same scale


Ionic Bond

Polar

Covalent

Covalent


If the difference in

electronegativities is between:

1.7 to 4.0 = Ionic Bond

0.3 to 1.7 = Polar Covalent

0.0 to 0.3 = Non-Polar Covalent

More magazines by this user
Similar magazines