Intramolecular forces

Ionic Compounds Ionic Compounds (SALTS)

formed by transferring electrons (giving/taking) occurs between a metal and a non-metal have an electro negativity difference greater than 1.7 unit is called "formula unit“

Since electrons are transferred, not shared, the atoms aren’t attached to each other like in a molecule

exist as solids, usually crystalline have high melting points

This is because of the strength of their bond. A stronger bond requires more energy to break

soluble in water conducts electricity in water fixed + and – parts (anions & cations )

EXAMPLES: KCl, NaF, KNO3

Crystalline Structure of Ionic Compounds

Metallic Bonds A metallic bond is a bond formed by the attraction between neighboring

metal nuclei and the electrons around them. metal atoms create a crystal lattice of positive metallic nuclei in a 'sea of

electrons'.

Electricity is the movement of electrons Metals are good at conducting electricity because their bonds allow the

electrons to flow freely because they are delocalized This means that they do not belong to any one atom but move freely about

the metal’s network of empty atomic orbitals.

Metallic Bond PropertiesElectrical & thermal conductivity as a solid or liquid

This is because of how freely the electrons can moveHigh melting and boiling points

This is because of the strength of their bond. A stronger bond requires more energy to break

Malleable (sheets) and ductile (wires)The delocalized electrons in the 'sea' of electrons in

the metallic bond, enable the metal atoms to roll over each other when a stress is applied.

Shiny appearance Photons of light do not penetrate very far into the

surface of a metal and reflect off the metallic surface.

Covalent Compounds formed by sharing electrons occurs between non-metals unit is called "molecule“ exists as liquids, gases, or non-crystal solids have low melting points

This is because a covalent bond isn’t as strong as the other two types of bonds

insoluble in water This is because covalent compounds to not have much of a difference in

charge conducts electricity in water may have slightly + and - parts or totally neutral

When they have a slight difference in charge, they are considered polar When there is no difference in charge, they are considered non-polar

EXAMPLES: NH3, CO2, CH4

Polar vs. Non-Polar Covalent CompoundPolar BondsBonds in which atoms share electrons

unequally are called polar covalent bonds. The electronegativity difference between the two

atoms is between 0.5 and 1.7

Non-Polar BondsBonds in which atoms share electrons equally

are called non-polar covalent bondsThe electronegativity difference between the two

atoms is below 0.5

Ionic, Metallic, Polar Covalent or non-polar covalent? Step 1: Figure out what type of element each atom is in

the compound (metal or non-metal)Metal + Metal = MetallicMetal + Non-metal = IonicNon-metal + Non-metal = Covalent (polar or non- polar)

Step 2: If it’s a covalent compound, you must find the difference in negativity to determine if it is polar or non-polar by looking that the chartNon-polar molecules have an electronegativity difference

of less than 0.5Polar molecules have an electronegativity difference of

greater than 0.5 but smaller than 1.7

Single, Double and Triple Covalent BondsSingle bonds

Only 1 electron pair is shared (total of 2 electrons)Requires the least amount of energy to breakHas the largest distance between nuclei of the 3 bonds

Double bonds2 electron pairs are shared (total of 4 electrons)Requires a moderate amount of energy to breakHas a medium distance between nuclei of the 3 bonds

Triple bonds3 electron pairs are sharedRequires the most amount of energy to breakHas the shortest distance between nuclei of the 3 bonds

Single, Double and Triple Covalent Bonds

How do I figure out if it’s a single double or triple bond?ANS: Create a Lewis dot structure!

Organic Chemistry Example: compare the carbon-carbon bond of the following compounds:

1. Ethane (C2H6)

2. Ethene (C2H4)

3. Ethyne (C2H2)

Which one has a single bond? Double bond? Triple Bond?