MEYER & MENDELEEV (1869): MEYER & MENDELEEV (1869):
Showed connection between atomic mass & Showed connection between atomic mass &
properties.properties.
• Mendeleev – given credit (published first).• Arranged by atomic mass.• Found that properties repeated.
• Predicted existence & properties of undiscovered elements. (Ex. Ge)
• Recognized discrepancies in properties. (Ex. Te & I)
MOSELYMOSELY (1913) – Discovered (1913) – Discovered
protons protons (Atomic #)(Atomic #)• Arranged elements by atomic #.
• Saw clear pattern of periodic properties (problem of discrepancies solved).
• Periodic Law – When elements are arranged by increasing atomic number, there is a periodic repetition of chemical
& physical properties.
MODERN PERIODIC TABLE:MODERN PERIODIC TABLE:
Boxes arranged by increasing atomic Boxes arranged by increasing atomic
##• Groups (families)– vertical columns.• Numbered by “a” & “b” or 1-18
• Elements in the same group share similar properties (Ex. Na & K – both in 1a)
• Representative elements (Main Group)
• Belong to “a” groups • (“s” & “p” block)• Wide range properties
PERIODSPERIODS - - Horizontal RowsHorizontal Rows Show # Energy LevelsShow # Energy Levels
• 7 periods on table• Various properties• Ex. Period 3 contains Na, Si, Cl, Ar• (has 3 energy levels)
QUIZQUIZ• 1) Mendeleev arranged elements by increasing ______.
• 2) How are elements arranged on the modern periodic table?
• 3) Sodium and magnesium are in the same _____.
• 4) Li & Na are in the same _____.
• 5) Which 2 elements have the most similar properties?
Na Mg K Ar
ELEMENT CLASSIFICATIONELEMENT CLASSIFICATION – – 3 main 3 main
types:types:
Metals, Nonmetals, MetalloidsMetals, Nonmetals, Metalloids
• Separated by “zigzag” line• Metals: (Left of zigzag) (except H)
• Properties: • Shiny & smooth (when clean)• Ductile (can draw into wire)• Malleable (hammer into sheets)• Good conductors (heat & electricity)• Often react with acids
GROUPS OF METALSGROUPS OF METALS
• 1a (1) = alkali metals• (red)• (not H)
• Most reactive metals • (Fr most active)
• 2a (2) = alkaline earth metals• (green)• Very reactive
TRANSITION ELEMENTS (Metals) TRANSITION ELEMENTS (Metals)
““dd ”” block; block; ““bb ”” groups or # 3-12 groups or # 3-12
• Ex. Au, Fe, Cu• Many transition metal compounds are
colorful:
INNER TRANSITION ELEMENTS INNER TRANSITION ELEMENTS
(Metals)(Metals)
””ff ”” block, 2 bottom rows (blue) block, 2 bottom rows (blue)
• 1st row (Lanthanide series)(Lanthanoid)
• 2nd row (Actinide series) (Actinoid)
QUIZ - METALSQUIZ - METALS
WHAT GROUP IS THIS?WHAT GROUP IS THIS?• 1) Group 1a (1)• 2) Group 2a (2)
• 3) Cu & Ag are in this group.
• 4) Bottom 2 rows are in this group.
• 5) Uranium is in this series.
• 6) Sm & Ce are in this series.• 7) Most reactive metallic
group.
• 8) Representative elements
NONMETALS – Right of NONMETALS – Right of
zigzag & Hzigzag & H
Day 2Day 2
• Properties:• Gases or brittle & dull solids• Only liquid is Br• Poor conductors
chlorine gas
• Groups:• 6a (16) = chalcogens (oxygen gp.)• 7a = halogens (very reactive)• 8a = noble gases (inert, unreactive, full outer shell)
NONMETALS - NONMETALS - What group is What group is
this?this?• 1) Group 6a (16)• 2) Group 7a (17)• 3) Group 8a (18)
• 4) Hydrogen is the only nonmetal placed with this group.
• 5) The most reactive nonmetal group.
METALLOIDS (SEMI-METALLOIDS (SEMI-
METALS)METALS) Elements along Elements along
zigzag (not Al)zigzag (not Al)
• Show properties of both metals & nonmetals
• Ex. Si & Ge – shiny, semi-conductor, brittle
• Used in computer chips, etc.
OTHER GROUPS OTHER GROUPS
NAMED FOR 1NAMED FOR 1stst ELEMENT: ELEMENT:• Group 3a (13) Boron group• Group 4a (14) Carbon group• Group 5a (15) Nitrogen group
• Groups contain metals, nonmetals & metalloids.
QUIZ – QUIZ – METAL, NONMETAL, METAL, NONMETAL,
METALLOIDMETALLOID• 1) Tell whether the following is a metal, nonmetal or metalloid?
• Sr Co P Sb Se• m m nm ml nm
• 2) An element is smooth, shiny, conducts electricity well, & reacts with acid.
• Which element is it? W Br As Ge
W=metal
PROBLEM:PROBLEM:
Which element is this?Which element is this?• 1) An element is a dull
solid, brittle, and does not conduct electricity or react with acid.
• Which element & gp.?• Mg Ge S O• S, chalcogens
• 2) An element is shiny, brittle, partly conducts electricity but does not react with acid.
• Zn Ge Kr I• Ge, Group 4A (carbon
gp.)
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