Class Notes
• How is the periodic table organized?
◦Colors in each section
◦Reference
◦Electron levels
◦Atomic numbers
• Video
◦"Disappearing Spoon" - the history of the periodic table
◦Gallium = low melting point, melts in tea
◦Groups = Columns (1-18)
‣ Elements with similar characteristics are in the same group
‣ Fluorine, chlorine, bromine, iodine: all used to clean; everything that cleans works
because there is a chemical reaction
‣ Alkali metals (Group A1) - one valence electron so very reactive; solids
‣ Alkaline earth metals (Group A2) - two valence electrons, so reactive but fairly stable
‣ Halogens (Group A7) - seven valence electrons
‣ Noble gasses (Group A8) won't react; noble = not interacting with the 'peasants'
◦Periods = Rows (1-7)
◦The number of the A group is the number of outer electrons (elements like to have 8)
‣ The 8A group is happy, so NOT REACTIVE
‣ 1A, 2A, and 3A will LOSE electrons, 5A, 6A, and 7A will GAIN electrons
‣ The fewer electrons you need to gain or lose, the more reactive the element is
‣ The number of valence electrons determines the chemical properties
◦CHNOPSSe - Nonmetals, C, H, N, O, P, S, Se, ◦Most elements on the periodic table are METALS
◦Transition metals = B groups
‣ Gold, silver, copper, platinum
‣ Worth of an element depends on the rarity and has more properties
History of the Periodic Table (156)
• Dmitri Mendeleev, Russian scientist, published his version of the periodic table in 1869 after
previous attempts from other scientists that did not gain much acceptance (right before German
scientist Lothar Meyer published his)
◦Created while working on a textbook for his students; meant to show the relationships
between the 69 elements; arranged information on notecards
◦Elements arranged by increasing atomic mass
◦Left spaces/question marks for elements that would be later discovered
Metals, Non-metals, and Metalloids
• Anything touching the "staircase" line is a metalloid (except for aluminum, a poor metal)
• Metals are to the LEFT of the line; Non-metals are to the RIGHT of the line
• Metals
◦Malleable = pounded into thin sheets
◦Ductile = formed into wire
◦Conductors of Heat and Electricity (varying levels though; different characteristics)
◦Luster = Shiny
◦Lose electrons when reacting
• Non-metals
◦Brittle = easily broken down
◦Poor conductors of heat/Good insulators
◦Not shiny
◦Non-ductile
◦Gain electrons when reacting
• Metalloids (combination of characteristics of metals and non-metals)
◦Semi-conductor
• These are all GENERAL characteristics; each elements has its own unique characters
6.1
Organizing the Elements
> Searching For an Organizing Principle
Searching For an Organizing Principle
How did chemists begin to organize the
known elements?
Chemists used the properties of
elements to sort them into groups
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6.1
Organizing the Elements
> Searching For an Organizing Principle
Chlorine, bromine, and iodine have very
similar chemical properties.
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6.1
Organizing the Elements
> Mendeleev’s Periodic Table
Mendeleev’s Periodic Table
How did Mendeleev organize his
periodic table?
Mendeleev arranged the elements in his
periodic table in order of increasing
atomic mass.
The periodic table can be used to predict
the properties of undiscovered elements.
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6.1
Organizing the Elements
> Mendeleev’s Periodic Table
An Early Version of Mendeleev’s Periodic Table
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6.1
Organizing the Elements
> The Periodic Law
How is the modern periodic table organized?
In the modern periodic table, elements are
arranged in order of increasing atomic
number.
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6.1
Organizing the Elements
> The Periodic Law
The periodic law: When elements are arranged
in order of increasing atomic number, there is a
periodic repetition of their physical and chemical
properties.
•The properties of the elements within a period
change as you move across a period from left
to right.
•The pattern of properties within a period
repeats as you move from one period to the
next.
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6.1
Organizing the Elements
> Metals, Nonmetals, and Metalloids
Metals, Nonmetals, and Metalloids
What are the three broad classes of
elements?
Three classes of elements are metals,
nonmetals, and metalloids.
Across a period, the properties of elements
become less metallic and more nonmetallic.
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6.1
Organizing the Elements
> Metals, Nonmetals, and Metalloids
Metals, Metalloids, and Nonmetals in the Periodic
Table
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Organizing the Elements
> Metals, Nonmetals, and Metalloids
Metals, Metalloids, and Nonmetals in the Periodic
Table
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Organizing the Elements
> Metals, Nonmetals, and Metalloids
Metals, Metalloids, and Nonmetals in the Periodic
Table
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Organizing the Elements
> Metals, Nonmetals, and Metalloids
Metals, Metalloids, and Nonmetals in the Periodic
Table
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6.1
Organizing the Elements
> Metals, Nonmetals, and Metalloids
Metals
Metals are good conductors of heat and electric
current.
•80% of elements are metals.
•Metals have a high luster, are ductile, and are
malleable.
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6.1
Organizing the Elements
> Metals, Nonmetals, and Metalloids
Uses of Iron, Copper, and Aluminum
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Organizing the Elements
> Metals, Nonmetals, and Metalloids
Uses of Iron, Copper, and Aluminum
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Organizing the Elements
> Metals, Nonmetals, and Metalloids
Uses of Iron, Copper, and Aluminum
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6.1
Organizing the Elements
> Metals, Nonmetals, and Metalloids
Nonmetals
In general, nonmetals are poor conductors of
heat and electric current.
•Most nonmetals are gases at room
temperature.
•A few nonmetals are solids, such as sulfur
and phosphorus.
•One nonmetal, bromine, is a dark-red liquid.
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6.1
Organizing the Elements
> Metals, Nonmetals, and Metalloids
Metalloids
A metalloid generally has properties that are
similar to those of metals and nonmetals.
The behavior of a metalloid can be controlled by
changing conditions.
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6.1
Organizing the Elements
> Metals, Nonmetals, and Metalloids
If a small amount of boron is mixed with silicon,
the mixture is a good conductor of electric
current. Silicon can be cut into wafers, and used
to make computer chips.
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6.1
Section Quiz
1. The modern periodic table has elements
arranged in order of
a. colors.
b. melting and boiling points.
c. increasing atomic mass.
d. increasing atomic number.
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6.1
Section Quiz
2.
Mendeleev arranged the elements in his
periodic table in order of increasing
a. atomic number.
b. number of protons.
c. number of electrons.
d. atomic mass
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6.1
Section Quiz
3.
Which one of the following is NOT a
general property of metals?
a. ductility
b. malleability
c. having a high luster
d. poor conductor of heat and electricity
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1) How did chemists being the process of organizing elements?
2) What property did Mendeleev use to organize his periodic table?
3) How are elements arranged in the modern periodic table?
4) Name the three broad classes of elements.
5) Which of these sets of elements have similar physical and chemical properties:
a) Oxygen, nitrogen, carbon, boron (same period, different groups)
b) strontium, magnesium, calcium, beryllium (different periods, same group)
c) nitrogen, neon, nickel, niobium (different period, different period)
6) Identify each element as a metal, metalloid, or nonmetal
a) gold
b) silicon
c) sulfur
d) barium
7) Name two elements that have properties similar to those of the element sodium
Anything in the 1A group (properties are similar within the groups, based on the valence electrons)