1. brief biochemistry

2. atoms Smallest unit of matter
# of protons = # of neutrons = # of electrons
Therefore… NO OVERALL CHARGE
Nucleus holds protons (+) and neutrons (0)
Orbitals hold electrons (-)

3. atoms Inner orbital can hold up to 2 electrons
Outer orbital can hold up to 8 electrons
Electrons on outer-most orbital are called valence electrons
“Happy” (stable) atoms have a full outer orbital OR OR

4. ions
When atoms don’t have full outer orbitals, they are not happy (stable)  + - Na Cl
Elements with FEWER than 4 valence electrons tend to lose electrons and become POSITIVE
Elements with MORE than 4 valence electrons tend to gain electrons and become NEGATIVE
If elements loose or gain electrons, they become ions

5. ions + - Na Cl
The positive ion (cation) is attracted to the negative ion (anion) forming an IONIC BOND

6. molecules
A molecule is a group of at least two atoms that are held together
The atoms of a molecule are held together by covalent bonds, which are very strong!
Covalent bonds occur when atoms that don’t have a full outer orbital SHARE valence electrons

7. intro to macromolecules
Macro = large (Large molecules)
Macromolecules are produced by, and found in, living cells
Macromolecules consist primarily of carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur
The four main types of macromolecules are carbohydrates, lipids, proteins, and nucleic acids