32 deg F 0 00 deg C Temperature SI kelvin but you can convert from Fahrenheit and Celsius Temperature of interstellar space is 2 73 K What is the temp on the Celsius and Fahrenheit scale C F 32 1 8 K C 273 15 273 15 2 73 K C 273 15 273 15 270 42 C Chapter 2 Atoms and Elements The structure of the atom The discovery of a negatively charged particle electron Coulomb C is the SI Unit of charge Charge of electron 1 602 x 10 19 C For convenience we identify the charge of an electron as equal to 1 in atomic units Proton has charge of 1 Charge of proton and electron are equal in magnitude but opposite in sign Plum Pudding Model inaccurate Nuclear Model accurate Most of the atom s mass and all of its positive charge are contained in the nucleus Most of the volume of the atom is empty space through which electrons are dispersed The atom is electrically neutral Neutrons neutral particles within nucleus that have mass Neutral Has one proton and one electron and no neutrons Number at top is number of protons Atomic mass is bottom number Hydrogen the simplest atom Atomic number Z number of protons de nes the element top Periodic table arranged so similar properties fall in columns Isotopes same number of protons but different number of neutrons N Mass number A sum of protons Z and neutrons N A Z N Periodic Table Carbon has 3 naturally occurring isotopes 12 C N 6 13 C N 7 14 C N 8 All have Z 6 A 39 K A Z N P 19 E 19 39 19 N N 20 Example how many protons neutrons and electrons are in a 39K atom Ion Atoms can lose or gain electrons to become charged particles or ions Can not change number of protons without becoming different atom Salt Na and Cl Cl e Cl Na 1e Na Na is a cation 11 protons and 10 electrons Cl is an anion 17 protons and 18 electrons A 197Au A Z N P 79 E 79 197 79 N N 118 How many protons neutrons and electrons are in an atom of 197 Au Give the complete chemical symbol for the ion with 26 protons 30 neutrons and 24 electrons Fe2 Atomic mass scale Set 12C to be exact t 12 0000000 Atomic mass units amu or u Atomic mass unit 1 12 the mass of a carbon atom containing 6 protons and 6 neutrons 1 amu 1 66054 x 10 27 kg Mass of the proton 1 00727u Mass of the neutron 1 00866 u Mass of the electron 0 00055 u Atomic Weight Bottom number on periodic table elements Weighted according to natural abundance 12C 98 89 12 0000 amu 13C 1 11 13 00335 amu 0 9889 x 12 0000 12C 0 011 x 13 00335 13C 12 01 Atomic Size Diameter of an atom 100 to 500 pm Diameter of nucleus 1 75 fm to 15 fm Note 1 fm 1 x 10 15 Angstrom A 10 10 m Diameter of U S penny us 19 mm The diameter of a copper atom by comparison is 2 6 A How many copper atoms could be arranged side by side in a straight line across the diameter of the penny The Mole and Avogadro s Number How can we count large amounts of atoms De ne convenient counting unit Mole abbreviated mol is the chemist s dozen 1 mol 6 022 x 10 23 Anything A pure silver ring contains 2 80 x 10 22 silver atoms How many moles of silver atoms does that ring contain 2 80 x10 22 Ag atoms 12 00 g 12X 1 mole 12C atoms 6 022 x 10 23 atoms 12C A mole is equal to the number of atoms in exactly 12 00000g of pure 12C Since all the masses in the periodic table are de ned relatives to 12C the mass of 1 mol of atoms of an element molar mass Molar Mass Units g mol Divide by Avogadro s number and multiply by molar mass how many atoms are in 4 58 g of sulfur a titanium cube contains 2 86 x 10 23 atoms What is the edge length of the cube the density of titanium is 4 50 g cm 3 Chapter 3 Bonding Ionic Compounds Molecular Compounds Writing Ionic Formulas Transfer of electrons between atoms Combine a positive ion s a metal With negative ions or non metal Held together by electrostatic Sharing of electrons between non metals H2O Name of element of cation metal Shortened base name of anion nonmetal with IDE ending KCl is potassium chloride Ag3N is silver nitride Rb2S is rubidium sul de Naming ionic compounds Compounds Monatomic Anions Transition metals Groups 3 12 Naming ionic compounds Some metals can form more than one cation It s charge must be speci ed for a speci c compound Transition metals with exception of Zn2 Sc3 and Ag and Pb and Sn Add the II III and IV to indicate the charge of the metals ion Otherwise name the same as for xed charges Write formula for iron III sul de Write formula for iron III oxide Naming compounds containing poly atomic ions Same as naming ionic compounds Use the name if the poly atomic ion when it occurs Li2Cr2O7 Lithium dichromate NH4NO3 ammonium nitrate Hydrated ionic compounds Some ionic compounds contain a speci c number of water molecules Name the ionic compound then add additional name to include the hydrate with pre x indicating the number of hydrates CoCl x 6H2O Cobalt II chloride hexahydrate Give the formula or name for the following ionic compounds Aluminum bromide Al 3 Br AlBr3 Cr2O3 Chromium III oxide Naming molecular compounds Pre x Name of rst element Pre x Name of second element with IDE ending Combining two no metals nitrogen and oxygen NO2 Mono nitrogen dioxide or nitrogen dioxide N2O dinitrogen monoxide N2O5 dinitrogen pentaoxide Naming acids Naming oxyacids Acids are molecular compounds that release H into solutions Their chemical formulas begin with H Aqueous aq means dissolved in water Hydro Base name of none metal with ic ending Acid HCl gas hydrogen chloride molecular compound Hack aq hydrochloride acid acid Contain hydrogen like acids Oxyanion anion containing nonmetal and an oxygen Ie nitrate NO3 and sul te SO3 2 from poly atomic list Ate ion Base name of Oxyanion with ic ending Acid HNO3 aq nitric acid Ite ion Base name of Oxyanion with ous ending Acid H2SO3 aq sulfurous acid