1. Do Now!!!
Write two interesting things you learned in last night’s article. Then turn in your Do Now sheet!
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2. Organizing and Classifying the Elements on the Periodic Table
Chapter 6.1 and 6.2
Organizing and Classifying the Elements on the Periodic Table
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3. Chapter 6.1
Organizing the Elements
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4. How are the elements organized on the periodic table?
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5. Early Organization of Elements
On 13 elements identified by the 1700’s
Chemists suspected other elements existed
Some where even named, but unable to isolate these elements
By 1775, 5 new elements were identified
Including hydrogen, oxygen, and nitrogen
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6. Early Organization of Elements
Early chemists used properties of elements to sort them into triads
Similar reactivity with metals
Colorless, odorless gases
Not all known elements could be grouped into triads
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7. Mendeleev’s Periodic Table
Russian chemist and teacher, Dmitri Mendeleev
In 1869, Mendeleev published the first table of elements
Organized elements into groups based on repeating properties
Mainly increasing atomic mass
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8. Mendeleev’s Periodic Table
L. Bernard, 2015
Published in 1869;
Left blanks for undiscovered elements
Organized by increasing atomic mass

9. Problems with Mendeleev’s Table
Created his table before scientists discovered the structure of atoms
What property of the atom would make organizing the periodic table by increasing atomic mass problematic???
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10. Modern Day Periodic Table
Organized by increasing atomic number
Periodic Law
When elements are arranged by increasing atomic number, there is a periodic repetition of their physical and chemical properties
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11. Metals, Nonmetals, and Metalloids
Three Broad Classes of Elements
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12. L. Bernard, 2015

13. Chapter 6.2
Classifying the Elements
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14. Reading the Periodic Table
Columns = Groups or Family
1A = Alkali Metals
2A = Alkaline Earth Metals
7A = Halogens (“salts”)
8A = Noble Gases
Rows = Period
Based on principle quantum number
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15. Reading the Periodic Table
Halogens
Group 7A
Very reactive elements
Combine with metals to make salts
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16. Reading the Periodic Table
Noble Gases (Inert Gases)
Group 8A
Rarely take part in reactions, most stable elements
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17. Reading the Periodic Table
Representative Elements
Groups 1A-7A
Wide range of physical and chemical properties
s and p orbitals are not completely filled
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18. Reading the Periodic Table
Transition Elements
B group of elements
Characterized by the presence of electrons in the d orbital
Once known as “rare earth metals”
Misleading since not all these elements are rare or from the earth!
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19. Reading the Periodic Table
Inner Transition Elements
Characterized by the presence of electrons in the f orbital
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20. Characteristics of Metals, Non-metals, and Metalloids
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21. Metals Most elements are metals
Good conductors of heat and electricity
High luster and sheen (able to reflect light)
Solid at room temperature
Ductile
Malleable
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22. Non-metals
Greater variation of physical properties among these elements
Most are gases at room temperature
However, a few are solids (sulfur and phosphorus) and one is a liquid (bromine)
Poor conductors of heat and electricity
Brittle
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23. B, Si, As, Te, At, Ge, Sb Metalloids
Properties of both metals and nonmetals
Changing the conditions can change whether a metalloid acts like a metal or a nonmetal
Etc: silicon is a poor conductor of electricity; when mixed with boron it will conduct electricity well
The 7 metalloids are:
B, Si, As, Te, At, Ge, Sb
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