2. How would you organize these…?

3. Early Periodic Tables J.W. Dobereiner John Newlands
Group elements in triads (sets of 3)
Based on chemical/physical properties
Didn’t work well with metals
John Newlands
Law of Octaves
Properties of elements seem to change every 8th elements

4. Modern Periodic Table Dmitri Mendeleev Periodicity Periodic Law
Groups elements by atomic mass
Groups = vertical columns
Periods = horizontal lines
Predicted details for elements not yet discovered
Periodicity
Repeating patterns at set intervals
Periodic Law
pattern in chemical and physical properties of the elements when they are arranged by increasing atomic numbers

5. Modern Periodic Table Henry Moseley Designed periodic table used today
Ordered elements by increasing atomic numbers

6. Reading the Periodic Table
Element
Atomic symbol
Atomic number
Atomic mass

7. Number of electrons in sublevels
Periods
Period shows the number of shells possible for those elements
2n2 = max # of electrons
Period #/ Shell #
Number of electrons in sublevels
Max # of electrons
In Shell
n=1 2
n=2 8
n=3 18
n=4 32
n=5 50
n=6 72
n=7 98

8. Groups “A” Group- representative elements Special Names:
Group # = Valence electron #
Special Names:
I A = Alkali Metals
II A= Alkaline Earth Metals
VII A= Halogens
VIII A= Nobel Gases

9. Element Ion Charges -1; F-, Cl-, etc… +4/-4
Elements are most stable when they have a full set (8) of valence electrons
A’s Group # = Ion charge
Group I A = +1; H+, K+, etc..
Group IIIA = +3; B+3, Al+3, etc..
Group VIIA =
Group VIA= -2; O-2, Se-2, etc…
Group IVA=
-1; F-, Cl-, etc…
+4/-4