1. Ch. 3 Sec.
2
Organizing the
Elements

2. Activity-Which is easier? Pg. 80
Your time (seconds) Your time (seconds)
RANDOM ORDER ROWS

3. Why is the Periodic
Table important to me?
 most useful tool
to a chemist
 organizes lots of
info. about all
known elements

4. Pre-Periodic Table Chemistry …
 …was a mess!!!
 No organization of elements.
 Imagine going to a grocery
store with no organization!!
 Difficult to find information.
 Chemistry didn’t make sense.

5. Dmitri Mendeleev: Father of the Table
HOW HIS SOME
WORKED… PROBLEMS…
 Put elements in rows  He left blank spaces
by increasing atomic for what he said were
mass. undiscovered
elements. (Turned
 Put elements in out he was right!)
columns by the way  He broke the pattern
they reacted. of increasing atomic
weight to keep similar
reacting elements
together.

7. The Current Periodic Table
 Mendeleev wasn’t too far off.
 Now the elements are put in
rows by increasing ATOMIC
NUMBER!!

8. Each square of periodic
table incl:
 element’s atomic number=
# of protons in its nucleus
 chemical symbol
 name
 atomic mass= avg. mass of
all isotopes of that element
15.9994

9. Chemical symbol
 1 or 2 letters
 ex: iron= Fe

10. Groups
 columns
 aka families
 18 groups
 eg: Group 15= nitrogen family
 each group has similar characteristics

11. Periods
 Horizontal rows
 7 periods

12. Periodic Table Song by Tom Lehrer

14. YouTube video-Meet the
Elements
 Periodic Table Rap-YouTube
 http://www.youtube.com/watch?
v=cAnOUwPfHlk&feature=related