pp. 31-35 CHEMISTRY

1. Atoms Smallest unit nucleus: center/core is most of the mass of the atom a. protons: + b. neutrons: 0 electron cloud: outermost level

1. Atoms Ion: charged atom due to gaining or losing electrons ( Na vs Na+ )

2. Element Pure substance that can’t be broken into other types of matter Each element has its own symbol that uses 1 or 2 letters

3. Compounds Substance made of two or more elements Ex: H2O, NaCl

4. Bonds covalent bonds (strong): 2 or more atoms share electrons ionic bonds (weak) : attractions between + and – ions by transferring electrons

5. Chemical Reactions (rxn) EX. NaOH + HCl  NaCl + H2O reactants: left side products: right side Exothermic: release energy like heat, explosion, light etc. Endothermic: requires energy to occur and takes it from the environment- feel cold

6. Activation Energy energy needed to start a rxn

NEED TO MEMORIZE THE FOLLOWING ELEMENTS AND COMPOUNDS FOR YOUR QUIZ AND TEST! H: hydrogen O: oxygen N: nitrogen C: carbon Na: sodium Cl: chlorine K: potassium S: sulfur COMPOUNDS H2O: water NaCl: sodium chloride/salt H2SO4: sulfuric acid HCl: hydrochloric acid NaOH: sodium hydroxide CO2: carbon dioxide O2: oxygen gas

7. Acid Acid: a solution in which [H+] > [OH-] Acid Properties tastes sour, highly corrosive, pH < 7

8. Base Base: a solution in which [H+] < [OH-] Base Properties: tastes bitter, feel slippery, pH >7

9. Neutral Pure Neutral water has a pH = 7

10. pH Scale pH: is a scale that measures the relative concentrations of hydrogen (H+) and hydroxide (OH-). One unit of change in pH = a change in 10x the acidity of basicity

10. pH power of Hydronium Measures acidity (from 0-14) and how much H+ is present. The closer to 0, the more H+ ions 0 up to 7 = acid 7 = neutral over 7 = base/alkaline Can use indicators to tell the pH ( phenol red, pH paper, litmus, BTB)