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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 COPY
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History of the Periodic Table
End of the 1700’s – less than 30 elements known Many elements discovered during 1800’s Many experiments done to determine atomic masses
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John Newlands 1864: if elements arranged by atomic mass - properties repeat every 8th element Law of Octaves did not work for all known elements Key idea was correct: Properties of elements do repeat in periodic way
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Mendeleev & Meyer Mendeleev produced 1st accepted PT: 1869
Elements ordered by ↑ atomic mass into columns with similar properties Predicted existence & properties of undiscovered elements Not totally correct more accurate atomic mass calculations showed some elements weren’t in right place
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Remember 1860’s: No subatomic particles yet discovered
Dalton’s billiard ball model of the atom
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1913 – Henry Moseley by 1913, protons & electrons discovered
Neutrons were predicted Moseley determined atoms of each element contain unique # protons (= atomic number) rearranged Mendeleev’s PT by atomic number instead of mass problems with elements in wrong place disappeared
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Periodic Law There is a periodic repetition of chemical and physical properties of elements when arranged by increasing atomic number
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Glenn Seaborg: 1950’s Lanthanide and Actinide Series
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Newlands Seaborg Mendeleev Mosley
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Vocabulary of PT Columns called groups or families
COPY Columns 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 Rows are called series or periods #1 thru 7
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Column numbering (1 18) left to right
Period numbering (1 7) top to bottom
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Structure of Periodic Table
Closely related to electron configuration of each element COPY
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Energy Levels = Row Number
Elements in same row have same # of principal energy levels so # of principal energy levels = to row # COPY
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Going Across Row 2: 2-8 Ne 18 (VIIIA) 2-7 F 17 (VIIA) 2-6 O 16 (VIA)
COPY 2-8 Ne 18 (VIIIA) 2-7 F 17 (VIIA) 2-6 O 16 (VIA) 2-5 N 15 (VA) 2-4 C 14 (IVA) 2-3 B 13 (IIIA) 2-2 Be 2 (IIA) 2-1 Li 1 (IA) Configuration Element Family
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Going Down Column 1: 2-8-18-32-18-8-1 Fr 7 2-8-18-18-8-1 Cs 6
COPY Fr 7 Cs 6 Rb 5 K 4 2-8-1 Na 3 2-1 Li 2 1 H Configuration Element Period
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Number of Valence Electrons
COPY 4 14 or IVA 3 13 or IIIA 2 2 or IIA 1 1 or IA Number of Valence Electrons Group
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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 COPY
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Classifying the Elements
COPY 2/3 (75%) of elements are metals Remaining elements: non-metals & metalloids (semi-metals) Metalloids: some properties of metals & some properties of nonmetals Staircase: dividing line between metals & nonmetals elements to left are metals (except H) elements to right are non-metals
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Properties of Metals Malleable – flattened into sheets
COPY Malleable – flattened into sheets Ductile – drawn into wires & tubes have Luster Good Conductors of heat & electricity Solid at room temperature (except Hg) Metals lose electrons & form positive ions “Metals are losers” Low ionization energy Low electronegativity
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Properties of Nonmetals
COPY generally gases or solids (except Br2) solids are Brittle solids are Dull poor conductors of heat & electricity Nonmetals gain electrons & form negative ions “Nonmetals are winners” High ionization energy High electronegativity Properties: OPPOSITE of metals
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Properties of Metalloids
COPY 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 nonmetallic properties Example:Si shiny like metal but brittle like nonmetal
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Names of Families (AKA group A elements)
COPY 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
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Transition Metals Groups 3 through 12 AKA group B elements
COPY 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
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Elements that are gases at STP
Diatomics: H2, N2, O2, F2, Cl2 Monatomics: noble gases He, Ne, Ar, Kr, Xe, Rn COPY
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Two Elements: liquid at room temperature
Br2 (non-metal) and Hg (metal) COPY
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All other elements are solids at room temperature
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