CHEMISTRY pp. 31-35
ATOMS Smallest unit nucleus: center/core is most of the mass of the atom a. protons: + b. neutrons: 0 electron cloud: orbitals of electrons (-)
Element pure substance that cannot be broken into other types of matter Distinguished by the number of protons each element has its own symbol that uses 1 or 2 letters
Isotope Isotope: different number of neutrons Changes weight Ex: C12 vs C14 Carbon 14 is heavier since it has two more neutrons
ions Ion: charged atom due to gaining or losing electrons ( Na vs Na+ ) + if it lost an electron - if they gained an electron
substance made up of 2 or more elements EX. NaCl, H2O COMPOUNDS substance made up of 2 or more elements EX. NaCl, H2O
COMPOUNDS held together by bonds covalent bonds (strong): 2 or more atoms share electrons Ionic Bonds (weak): attractions between ions
PROPERTIES OF WATER Water has a positive (+) and negative (-) “pole” Pulls apart molecules like NaCl (ionic bond)
WATER BONDING hydrogen bonds: bonds between Hydrogen atoms Ex: hold molecules of H2O together Bond Strength: Covalent > Ionic >Hydrogen
CHEMICAL REACTIONS EX. NaOH + HCl NaCl + H2O reactants: compounds rearranged (left side) products: compounds created (right side)
CHEMICAL REACTIONS EX. NaOH + HCl NaCl + H2O Exergonic/exothermic: release energy – feels warm endergonic/endothermic: requires energy-feel cold Activation Energy: amount of energy needed to start the reaction
Energy Diagram W/O a catalyst
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
GEMS Lab (due today) Biochem Vocabulary #1 (due tomorrow)
Biochem Vocab #1 Draw and Label Energy Diagram on Page 37 Word Definition Picture/Example Atom Compound Isotope Ion Covalent Bond Ionic Bond Hydrogen Bond Activation Energy Draw and Label Energy Diagram on Page 37