Ionic and Covalent Bonding [Chaps 6.3-6.4]
Metal +Nonmetal=Ionic Bond
Recall positive is attracted to negative charge
When a metal atom donates an electron to a non-metal atom, an Ionic bond occurs
Ionic Bonds are Predictable
Ion charges of Calcium and Fluorine:
Always from neutral compounds
Al3+ and O2-
These compounds are very stable over time
Sharing can bring happiness
In Ionic Bonding: The transfer of the electrons from one atom to a different atom brings happiness (energy stabilization) to both
But what happens if both atoms want an extra electron? They can both be happy if they share the electrons = COVALENT bonding
Sharing of TWO electrons always forms one covalent bond
Non-metal with Non-metal
Multiple Covalent Bonds
Extra sharing means extra strength and shorter
Single bonds> double bonds > triple bonds
Carbons always has 4 bonds (often in multiple bonds)
Oxygen always has 2 bonds
Hydrogen and Halogens only have 1 bond
Forming neutral and stable compounds
Once the molecule is neutral (considering the ion charges of each atom)
Determine how many of each atom
Use each atom’s atomic mass (g/mol)
Find the overall atomic mass of the whole molecule (g/mol)
This value can be used in dimensional analysis to solve problems
Calculating Molar Mass
To calculate Molar Mass
1. Determine how many atoms of each element are in the molecule
2. Multiply the atomic mass of each element by how many of that atom are present
3. Add up to determine the total molar mass i.e. Al2(SO4)3
Al: 26.98 X 2 = 53.96
S: 32.07 X 3 = 96.21
O: 16.00 X 12 = 192.00
Molar Mass = 342.17 g/mol
Organic Chemistry- The chemistry of Life [Chaps 6.5-6.8 and 12.1]
Simple Atoms, Complex Chemistry
Organic chemistry is the study of compounds made from primarily carbon, hydrogen and oxygen
A few other elements (N, P, S) provide functionality and usefulness
Based primarily on the extreme flexibility of carbon to form long-chain structures of itself
Chemistry of Carbon
Carbon always makes 4 covalent bonds
Most often with other carbon (or hydrogen) as a back bone
Little useful functionality
Molecules containing only carbon and hydrogen are called hydrocarbons
Chemistry of Carbon
Draw condensed and skeletal structures of diethyl ether, a compound once used as a general anesthetic Chemistry of Carbon
Research suggests that drinking green tea may help boost the immune system. Ethylamine (below), produced when one of the compounds in green tea is broken down in the liver, may be responsible for this immune response. Draw condensed and skeletal structures for this molecule.
We have described a covalent bond as consisting of a shared pair of valence electrons.
This is not the complete story – electrons in a covalent bond are not always shared equally between two atoms.
An unequal sharing of electrons is attributed to differences in electro negativity.
Electro negativity is the ability of an atom to attract bonding electrons.
Polar covalent bond
When the electrons in covalent bonds are shared by atoms with different electro negativities, a polar covalent bond results.
In a polar covalent bond, the unequal sharing of electrons gives the bond a partially positive and partially negative end (pole).
Attraction between molecules
A hydrogen bond is the interaction of a N, O, or F atom with a H atom that is covalently bonded to different N, O, or F atoms. Ion-to-Ion attractions
Dipole-dipole forces are the attraction of neighboring polar groups for one another.
London forces between non-polar molecules
(very weak attraction)
Greater surface area leads to stronger London force attraction
Saturated vs. Unsaturated Hydrocarbons [Chaps 12.1-12.6]
Multiple Bonds possible
Carbon can make single, double, triple bonds
Ring Structures are also available: Benzene
Saturated vs. Unsaturated