What is the periodic table?

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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

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History of the Periodic Table

• End of the 1700s less than 30 elements known
• Many elements discovered during 1800s
• Many experiments done to determine atomic masses

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John Newlands

• 1864 if elements arranged atomic mass their
  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

• 1869 Mendeleev produced 1st accepted periodic
  table
• Elements ordered by increasing atomic mass into
  columns with similar properties
• Predicted the existence properties of
  undiscovered elements
• Not totally correct
• more accurate atomic mass calculations showed
  some elements werent in the right place

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Remember

• 1860s No subatomic particles yet discovered
• Daltons 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
  a unique number of protons
• ( atomic number)
• Moseley rearranged Mendeleevs 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 the elements when they are
  arranged by increasing atomic number

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Glenn Seaborg 1950s

• Lanthanide and Actinide Series

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Newlands
Seaborg
Mendeleev
Mosley
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Vocabulary of the PT

• 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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Structure of the Periodic Table

• Closely related to electron configuration

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Energy Levels Row Number

• Elements in same row same of principal energy
  levels
• of principal energy levels to row

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Going Across Row 2
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Going Down Column 1
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Valence Electrons

• Elements in same column have same valence
  electrons.

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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

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Classifying the Elements

• 2/3 of elements are metals
• Remaining elements are non-metals and metalloids
  (semi-metals)
• Metalloids have some properties of metals and
  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 pounded into sheets
• Ductile drawn into wires
• Have Luster
• Good conductors of heat electricity
• Solid at room temperature (except Hg)
• Metals lose electrons to form positive ions
  Metals are losers
• Low ionization energy
• Low electronegativity

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Properties of Nonmetals

• 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 are the OPPOSITE of metals

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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
  nonmetallic properties
• ExampleSi
• shiny like a metal but brittle like a nonmetal.

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Names of Families(AKA group A elements)

• Group 1 Alkali Metals
• Group 2 Alkaline Earth 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
• Actinide and Lanthanide series inner transition
  elements
• 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

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Elements that are liquids at STP

• Br2 (non-metal) and Hg (metal)

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• All other elements are solids at room temperature