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