electro- negativity. ionic covalent continuum when chlorine and hydrogen react the covalently bonded...

Electro-negativity

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

ElectronegativityElectronegativityWhat is it?

• Electronegativity is the power of an atom to attract electron density

Remember the above definition …

in a covalent bond

Or in layman's terms the “attractiveness” of an atom to

electrons in a bond

ElectronegativityElectronegativityPauling’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

ElectronegativityElectronegativityPauling’s electronegativity scale

ElectronegativityElectronegativityPauling’s electronegativity scale

F

ElectronegativityElectronegativityPauling’s electronegativity scale

F4.0

ElectronegativityElectronegativityPauling’s electronegativity scale

Li1.0

F4.0

ElectronegativityElectronegativityPauling’s electronegativity scale

Li1.0

Be1.5

F4.0

ElectronegativityElectronegativityPauling’s electronegativity scale

Li1.0

Be1.5

B2.0

F4.0

ElectronegativityElectronegativityPauling’s electronegativity scale

Li1.0

Be1.5

B2.0

C2.5

F4.0

ElectronegativityElectronegativityPauling’s electronegativity scale

Li1.0

Be1.5

B2.0

C2.5

N3.0

F4.0

ElectronegativityElectronegativityPauling’s electronegativity scale

Li1.0

Be1.5

B2.0

C2.5

N3.0

O3.5

F4.0

ElectronegativityElectronegativityPauling’s electronegativity scale

Li1.0

Be1.5

B2.0

C2.5

N3.0

O3.5

F4.0

Na0.9

Mg1.2

Al1.5

Si1.8

P2.1

S2.5

Cl3.0

ElectronegativityElectronegativityPauling’s electronegativity scale

H He

Li1.0

Be1.5

B2.0

C2.5

N3.0

O3.5

F4.0

Ne

Na0.9

Mg1.2

Al1.5

Si1.8

P2.1

S2.5

Cl3.0

Ar

ElectronegativityElectronegativityPauling’s electronegativity scale

H2.1

He

Li1.0

Be1.5

B2.0

C2.5

N3.0

O3.5

F4.0

Ne

Na0.9

Mg1.2

Al1.5

Si1.8

P2.1

S2.5

Cl3.0

Ar

ElectronegativityElectronegativityPauling’s electronegativity scale

H2.1

He-

Li1.0

Be1.5

B2.0

C2.5

N3.0

O3.5

F4.0

Ne-

Na0.9

Mg1.2

Al1.5

Si1.8

P2.1

S2.5

Cl3.0

Ar-

So what does all this mean? Same atoms bonding

= same electronegativity = pure covalent bond

Different atoms bonding=different electronegativity

= Polar covalent or Ionic bondConfused? How do we tell which one?

Difference in electronegativity Covalent and ionic are a opposite ends of the same scale

Covalent

Ionic Bond

Polar 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