1. Ch3.4 Introduction to the Periodic Table
Organization of the Elements

2. Mendeleev: Father of the Periodic Table
Mendeleev is best known for his work on the periodic table; arranging the 63 known elements into a Periodic Table based on atomic mass, which he published in Principles of Chemistry in 1869
Mendeleev provided for variance from strict atomic weight order, left space for new elements, and predicted three yet-to-be-discovered elements including eke-silicon and eke-boron. His table did not include any of the Noble Gases, however, which had not yet been discovered.

3. Metals, Nonmetals, Metalloids
The periodic table is further divided into two broad categories of metals and nonmetals. Metals make up a majority of the table. Between the dividing line there is a class of elements that have properties of both metals and nonmetals. These elements are referred to as metalloids.
Non metals: halogens, noble gases, H, C, N, O, P, S, Se
Metalloids: B Si, Ge, As, Sb, Te, *(At)
Metals: The remainder of the elements
Actinides: all of the elements following actinium
Lanthanides: all of the elements following lanthanum

4. Organization of the Periodic Table
Horizontal rows in the table are referred to as Periods.
Hydrogen is period 1, Lithium is period 2, etc.
Vertical columns in the table are Groups or Families.
Group 1 is called alkali metals, except H
Group 2 is called alkaline earth metals
Group 17 are called halogens
Group 18 are called noble gases
Groups 1,2,13-18 are called main group elements
Groups 3-12 are called transition metals