Chapter 12: bonding

Covalent vs Ionic Bonding

Chemical Bond

• Bond between two or more elements
• It is formed when either electrons are shared
• Energy is stored within all chemical bonds

Covalent Bonds

• bond formed between two non-metals
• atoms share valence electrons
• the sharing is polar or non-polar

Covalent Bond Polarity

Polar Covalent

• the unequal sharing of valence electrons
• results in relatively charged molecules

Non-polar covalent

• the equal sharing of valence electrons
• no relative charge

Ionic Bonds

• formed between a metal and non-metal element
• valence electrons are transferred, not shared
• atoms become ions
• cation: the positively charged atom
• anion: negatively charged atom

Covalent and Ionic Bond similarities

• involve valence electrons
• bonds between two or more elements
• result in either relative charge or certain charge

Covalent and ionic bond differences

• covalent involves two non-metals
• ionic involves a non-metal and metal
• ionic bonds transfer electrons
• covalent bonds share electrons

Covalent and ionic bond differences

• covalent involves two non-metals
• ionic involves a non-metal and metal
• ionic bonds transfer electrons
• covalent bonds share electrons

Electrostatic Attraction
-the attraction between positive and negative ions that makes them bond

What is Electronegativity

• The relative ability of an atom to attract shared electrons
• The range values from 4.0 to o.7
• The more similar the atoms are, the less polarity there is
• The less similar the atoms are, the more polarity there is

Polarity

• Depends on the difference between the electronegativity values of the atom
• Atoms with similar electronegativities= little polarity
• atoms with greater  electronegativity=greater polarity

Determining Polarity

• Greater number of electronegativity - less number of electronegativity
• Use the polarity scale to see if it's non polar covalent, nonpolar covalent
• Or ionic

Determining the type of bond

• 0.0 -> 0.4 = non polar covalent
• 0.4 -> 2.0 = Polar Covalent
• 2.0 -> 4.0 = Ionic

Untitled Slide

Dipole Moment

• A molecule that is polar and has a negative pole
• Any diatomic (two-atom) molecule that has a polar bond has a dipole moment.
• Least amount of electronegativity are pulled to electrons with the most

Untitled Slide

Lewis Dot Diagrams

• Show only the valence electrons and the chemical symbol of the element
• When a bond is formed, dots are replaced with dashes
• The remaining dots show the un-bonded electron pairs

Types of bonds

• Single Bond: Sharing one pair of electrons
• Double Bond: Sharing two pairs of electrons
• Triple Bond: Sharing three pairs of electrons

Resonance Structures

• When there is more than one possible lewis structure

The end