1. Chap. 2 : Chemistry

2. Makeup of matter --- matter – anything that has mass and takes up space. (volume)
A. Atoms – simplest particle of an element.
1. Nucleus – center of atom, contains protons (p+) and neutrons (n).
p n = atomic mass
2. electrons – (-) charge, orbit around nucleus in shells or orbitals.
3. neutrons (n) – atomic mass – atomic number

3. *** atomic number – tells # of p+, e-.
B. Orbitals
- family – row going down, tells # of e- in outer shell.
- period – row going across, tells the # of electron shells.
*** All atoms want to be stable !!
Stable arrangements are having a full outer shell which is 8e- or 2e-(if only 1 shell)

4. *** e- in shells : 1st – 2e- 2nd – 8e- 3rd – 18e- 4th – 7th – 32e-
C. Bonding – atoms bond to become stable Ionic bonds – transfer of e-, forms ions. Done between families 1,2,3,5,6,7 . Ex. Na + Cl NaCl

5. --- elements combine to form compounds. Ex. H2O , C6H12O6
2. Covalent – sharing of e-. Done with family 4 and also H. Ex. H + Cl HCl
D. Elements – purest substance – cannot be broken down into anything simplier.
--- elements combine to form compounds. Ex. H2O , C6H12O6
--- molecule – smallest part of a compound.

6. III. Chemical Reactions A. Na + Cl NaCl
II. Energy – ability to do work activation energy – amount of energy needed to start a chemical reaction. (enzymes lower activation energy)
III. Chemical Reactions
A. Na Cl NaCl
(reactants) (yields) (products)
-- subscript – tells # of atoms of 1 particular element.
Ex. H2(subscript)
-- coefficient – tells # of

7. ** subscript x coefficient = total # of atoms of a particular element.
molecules of a particular element or compound. Ex 2H2O (2 molecules of water)
** subscript x coefficient = total # of atoms of a particular element.
ex. 6C4H8O4 ___ C ___ H ___ O
B. Energy Transfer in Reactions
1. Exergonic Reactions – release energy (feel hot)

8. 2. Endergonic reactions – absorb energy (feel cold).
IV. Solutions
- mixture of one or more substances. Made up of :
a. – substance being dissolved solute.
b. solvent – substance being dissolved into.
ex. Sugar (solute) water(solvent)

9. 2. Hydronium ion (H+) – solution with more H+ than OH-.
IV. Acids/Bases Hydroxide ion (OH-) – solution with more OH- than H+. Becomes basic (alkaline).
2. Hydronium ion (H+) – solution with more H+ than OH-.
Becomes acidic.
pH scale
blood ammonia
Acidic HCl neutral (H20) basic

10. each increase in pH scale # is 10x greater than the # before
** each increase in pH scale # is 10x greater than the # before. 4 is 100x more acidic than 6.
Buffers – neutralize acids or bases. Ex. Tums, rolaids