1. The Periodic Table
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4. J.W. Dobereiner ( )
discovered the existence of families of elements with similar chemical properties
classified elements based on “triads”
Li Ca S Cl Mn
Na Sr Se Br Cr
K Ba Te I Fe
all elements could not be grouped this way

5. Dmitri Mendeleev (1829-1869) Russian chemist and teacher
organized a “Periodic Table” (only knew about 63 elements at the time) based on increasing atomic mass
the properties of elements had something to do with their mass
he even left empty spaces to be filled in later

8. Main classes of elements

9. Metals about 80% of elements are metals
good conductors of heat and electricity
shiny
have high melting points
ductile
malleable
will corrode (rust) in water or air
tendency to lose electrons

12. Nonmetals or gases
located to the right of the “zig-zag line” in the periodic table
often are different from one another
dull
do not conduct heat and electricity
not malleable nor ductile
tendency to gain electrons

13. Metalloids only 7 elements on the “zig-zag line”
have some characteristics of both metals and nonmetals

14. Stop for Day 1 when shown with Periodic Table video

15. Design of the Table Groups are the vertical columns.
elements have similar, but not identical, properties
most important property is that they have the same # of valence electrons

16. Hydrogen (H) and helium (He) are special elements
Hydrogen (H) and helium (He) are special elements. Hydrogen can have the talents and electrons of two groups, one and seven. To scientists, hydrogen is sometimes missing an electron, and sometimes it has an extra. Helium is different from all of the other elements. It can only have two electrons in its outer shell. Even though it only has two, it is still grouped with elements that have eight (inert gases).

19. Periods are the horizontal rows
do NOT have similar properties
however, there is a pattern to their properties as you move across the table

20. Chemical Families or Groups
Alkali Metals
soft metals
most reactive of the metals because they all lose one valence electron very easily
results in a positively charged ion (cations) with a 1+ charge

22. Alkaline Earth Metals harder and more dense than alkali metals
not as reactive as the alkali metals
characterized by the loss of two electrons
results in a positively charged ion (cations) with a 2+ charge

24. Transition Metals (Elements)
display typical metallic characteristics ductile– malleable, shiny, conductivity
form a number of positively charged ions (cations )
can share or give away valence electrons to make lots of different compounds

26. Halogens characterized by gaining one electron
results in a negatively charged ion (anion) with a 1- charge
Form diatomic molecules -- (F2 Br2 I2 Cl2 )
Fluorine is the most reactive of the elements

27. Noble Gases mostly unreactive due to completely full s and p orbitals
colorless, odorless gases

29. Mixed Groups not as similar to each other as other groups
usually named after the first element in the group (B C N O)
can form cations or anions depending on the conditions / elements combined with

30. Rare Earth or Inner Transitional Elements
many are synthetically produced
composed of the lathanoid and actinoid series
have been separated from the others to make the table not as wide
used in the nuclear industries, metallurgy, ceramics, electrical components…