1. I. Atoms and Bonding

2. Atoms 1. Make up everything
a. Have electrons that are negative, protons that are positive and neutrons that are neutral.
2. Elements are pure samples of matter
3. Ions are charged atoms
4. Can bond in an attempt to fill outer levels of electron clouds.

3. B. Bonding 1. Compound is a group of elements held together by bonds
2. Covalent bonds
a. Formed when electrons are shared
b. Called a molecule
c. Fills the outer electron shell
d. Very strong and specific

5. 3. Ionic bonds
a. Exchange of electrons
b. Held together by the ions charges attracting each other
c. Will break apart in water

7. 4. Hydrogen bonds
a. Linking of polar molecules
1. polarity- having areas of unequal charges
b. Weak
c. Important for DNA and Proteins