What is the periodic table? compact way of organizing elements contains a lot of information allows us to make predictions about behavior and properties of elements Elements History of the Periodic Table End of 1700s less than 30 elements known Many elements discovered during 1800s Many experiments done to determine atomic masses John Newlands 1864: if elements arranged by atomic mass - properties repeat every 8 th element Law of Octaves did not work for all known elements Key idea was correct: Properties of elements do repeat in periodic way Mendeleev & Meyer 1869: Mendeleev produced 1 st accepted PT Elements ordered by atomic mass into columns with similar properties Predicted Predicted existence & properties of undiscovered elements Not totally correct more accurate atomic mass calculations showed some elements werent in right place Remember 1860s: Daltons billiard ball model of the atom No subatomic particles yet discovered 1913 Henry Moseley by 1913, protons & electrons discovered neutrons were predicted Moseley determined atoms of each element contain unique # protons (= atomic number) re-arranged Mendeleevs PT according to atomic number instead of atomic mass problems with elements in wrong place disappeared Periodic Law increasing atomic number There is a periodic repetition of chemical and physical properties of elements when arranged by increasing atomic number Glenn Seaborg: 1950s Lanthanide and Actinide Series Seaborg Mendeleev Mosley Newlands Vocabulary of PT groupsfamiliesColumns called groups or families Today: #1 thru 18, Arabic numerals Past: A & B groups, Roman numerals A-Group Columns 1,2,13-18 (= representative elements) IA 8A B-Group Transition metals (columns 3-12) IB - 8B seriesperiodsRows are called series or periods #1 thru 7 Column numbering (1 18) left to right Period numbering (1 7) top to bottom Structure of Periodic Table Closely related to electron configuration of each element Energy Levels = Row Number Elements in same row have same # of principal energy levels so # of principal energy levels = to row # Going Across Row 2: 2-8Ne18 (VIIIA) 2-7F17 (VIIA) 2-6O16 (VIA) 2-5N15 (VA) 2-4C14 (IVA) 2-3B13 (IIIA) 2-2Be2 (IIA) 2-1Li1 (IA) ConfigurationElementFamily Valence Electrons Chemical behavior determined by # valence electrons Elements with same # valence electrons will have similar chemical properties Elements in same column have similar chemical properties Going Down Column 1: Fr Cs Rb K Na3 2-1Li2 1H1 ConfigurationElementPeriod Valence Electrons 414 or IVA 313 or IIIA 22 or IIA 11 or IA Number of Valence Electrons Group Classifying the Elements metals2/3 (75%) of elements are metals non-metals metalloidsRemaining elements: non-metals & metalloids (semi-metals) Metalloids: have properties of both metals & non-metals Staircase:Staircase: dividing line between metals & non-metals elements to left are metals (except H) elements to right are non-metals Properties of Metals malleable flattened into sheets ductile drawn into wires & tubes have Luster good conductors of heat & electricity solid at room temperature (except Hg) Metals are losersmetals lose electrons & form positive ions Metals are losers low ionization energy low electronegativity Properties of Non-metals generally gases or solids (except Br 2 ) solids are brittle solids are dull poor conductors of heat & electricity non-metals gain electrons & form negative ions Nonmetals are winners Nonmetals are winners high ionization energy high electronegativity Properties of Metalloids 7 metalloids: 5 on right of staircase: B,Si,As,Te,At 2 on left of staircase: Ge,Sb Each metalloid has some metallic and some non- metallic properties example: Si shiny like metal but brittle like non-metal Names of Families (AKA group A elements) Group 1 = Alkali Metals Group 2 = Alkaline Earth Metals Groups 3-12: Transition metals Group 13 = Boron family Group 14 = Carbon family Group 15 = Nitrogen family Group 16 = Oxygen family Group 17 = Halogens Group 18 = Noble Gases Transition Metals Groups 3 through 12 AKA group B elements Actinide & Lanthanide series inner transition elements put the COLOR in your life form brightly colored salts/solutions Elements that are gases at STP Diatomics: H 2, N 2, O 2, F 2, Cl 2 Monatomics: noble gases He, Ne, Ar, Kr, Xe, Rn Two elements are liquid at room temperature Br 2 (non-metal) and Hg (metal) All other elements are solids at room temperature