Download The Periodic Table Notes

Developing the
Periodic Table
Early Element Classification
Mendeleev’s First Periodic Table
Mendeleev’s First Periodic Table
Mendeleev’s Periodic Table
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Arranged by increasing atomic mass
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Some elements did not follow the trend, why?
Their atomic numbers were in different orders than their atomic masses
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Modern periodic tables are arranged by atomic number, why did Mendeleev arrange his by
atomic mass?
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Rutherford discovered the nucleus in 1911, 40 years after Mendeleev first arranged the
elements
Grouped by properties
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Fluorine, Chlorine, Bromine, and Iodine were all placed into the same group because they had
similar properties and bonded with other elements in the same ratios
Adding to Mendeleev
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In 1894, the gas argon (Ar) was discovered by John William Strutt and Sir
William Ramsay
The next year, the gas helium (He) was proven to exist on earth
Sir Ramsay proposed a new group, the noble gases, be added to the periodic
table
Krypton (Kr), xenon (Xe), and radon (Rn) were all added to the noble gases as
they were discovered
Modern Periodic Table
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Arranged by increasing atomic number
A vertical column, known as a group contain elements with similar properties
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A horizontal row, known as a period, adds an energy level to the atom for each
row
Group 1 - The Alkali Metals
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Have one valence electron
Soft and silvery in color
Metals which are good conductors of heat and electricity
Low densities, low boiling points, low melting points
React violently with water
https://www.youtube.com/watch?v=m55kgyApYrY
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Group 2 - The Alkaline Earth Metals
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Have two valence electrons
Are lustrous and silvery-white
Are somewhat reactive
React with water to form hydroxides which are basic
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Groups 3-12 Transition Metals
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Have various numbers of valence electrons
We indicate the charges of their ions with Roman numerals
○ Iron (IV) = Fe4+
○ Copper (II) = Cu2+
Are less reactive than alkali metals
Group 17 or 7A - The Halogens
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Have seven valence electrons
Very good at stealing an electron from other compounds which make them great
oxidizers
Known as halogens because they react with metals to create salts
At room temperature, fluorine and chlorine are gases, bromine is a liquid, and iodine is a
solid
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Group 18 or 8A - The Noble Gases
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Have full valence energy levels
Are inert (unreactive) because they are so stable
Gases at room temperature
He
X
Metals, Metalloids, and Nonmetals
Metalloids:
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Boron
Silicon
Germanium
Arsenic
Antimony
Tellurium
Polonium
Metals = Left
Nonmetals = Right + Hydrogen
Diatomic Elements
Some elements form diatomic (two atoms) molecules in their elemental form.
These include:
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Hydrogen
Nitrogen
Oxygen
Fluorine
Chlorine
Bromine
Iodine
Oxidation Numbers
The oxidation number is the charge that an ion of a group in the periodic table will usually
have.
Write these on your white periodic table
Oxidation Numbers
Oxidation numbers are related to the number of valence electrons
Valence electrons are the number of electrons in the outermost energy level of an
atom
The Roman numerals next to the As in the column heading tell how many valence
electrons are in that group
Practice
Which element is in group 2 and period 7 of the periodic table?
Which element is in group 3A and period 3 of the periodic table?
Which element is in group 18 and period 1 of the periodic table?
Practice
Which set of elements contains a metalloid?
A. K, Mn, As, Ar
B. Li, Mg, Ca, Kr
C. Ba, Ag, Sn, Xe
D. Fr, F, O, Rn
Practice
The most reactive family of metals is the
A.
B.
C.
Transition metals
Alkaline earth metals
Alkali metals
Which of the following is most likely to have similar properties to calcium?
A.
B.
C.
Potassium
Barium
Scandium
Practice
Which of the following is most likely to have an ion with a charge of +3?
A.
B.
C.
Sodium
Aluminum
Silicon
Which of the following is most likely to have an ion with a charge of -2?
A.
B.
C.
Fluorine
Krypton
Oxygen
Practice
Name a main group element with 6 valence electrons.
Name a main group element with 1 valence electron.
Name a main group element with 3 valence electrons.
Practice: Average Atomic Mass
Find the average atomic mass of chlorine given 35Cl is 75.77%
abundant and 37Cl is 24.23% abundant.
Find the average atomic mass of iodine given 127I is 80% abundant,
126
I is 17% abundant, and 128I is 3% abundant.