1. Quote of the day
How far you go in life depends on your being tender with the young, compassionate with the aged, sympathetic with the striving, and tolerant of the weak and strong. Because someday in your life you will have been all of these.

2. Theoretical Chemistry
The Periodic Table
Theoretical Chemistry

3. Origin of Periodic Table
Triads - groups of 3 elements with similar properties
(Dobereiner – 1817)
Law of Octaves – properties of elements repeat every 8 elements
(Newlands – 1863)

4. Origin of Periodic Table
Dimitri Mendeleev – 1869
Properties of elements are periodic functions of their atomic masses.
Developed 8 column table
Left spaces for undiscovered elements
Columns contained elements with similar properties
Problems with Ni, I, K (Why?)

5. Origin of Periodic Table
X-ray experiments by Mosley (1913) led to discovery of atomic numbers.
Modern Periodic Law – properties of elements are periodic functions of their atomic numbers.

6. Organization of Periodic Table
Rows are called periods.
Columns are called families or groups.
All elements in a family have similar properties.
Octet Rule – elements with 8 valence electrons are unreactive

7. The Periodic Table of Elements
The P.T. is made up of
Groups/Families (columns)
Periods (rows)

8. The groups are further categorized as follows:1 8
Main Group (A) 2 3 4 5 6 7
Group B

9. The groups may also be broken down into
(including Hydrogen)
Non-Metals
Metals (not including Hydrogen)

10. Each group is then further classified as follows:
Alkaline Earth
Noble Gases
Each group is then further classified as follows:
Metalloids
Alkali
Halogens
Transition Metals
Stair step
Inner Transition Metals

11. The Inner Transition Metals are classified as follows:
Lanthanides
Actinides