Difference in Electronegativity Affects the Bond Type

Electronegativity differences between bonding elements is used to predict the bond type.

H2 – Electronegativity difference = 2.20 – 2.20 = 0 so a Covalent bond is formed.

HF – Electronegativity difference = 4.00 – 0.96 = 3.04 so an Ionic bond is formed

Ionic Bonds

• Held together by electrical attraction

•Strong; hard to break

Covalent Bonds

• Held together by shared electrons

• Not as strong

ELECTRONEGATIVITY DIFFERENCE

4 Step Process: Drawing Lewis Dot Structures

Key consideration – The octet rule

Step 1: Arrange atoms• Central atom lower electronegativity

Step 2: Add up the valence electrons of all atoms

Step 3: Draw single bonds• Subtract 2 electrons for each single bond from total counted in Step 2

Step 4: Deal out remaining electrons• Satisfy octet rule (except for Hydrogen)

Comparing and Contrasting Ionic and Covalent Bonds

Ionic Bond Covalent Bond

Electrons

BondElectronegativity Differences

State

Melting Pt.

Conductivity

Water Solubility