1. Section 2 Tour of the Periodic Table p. 111
Chapter 4
Section 2
Tour of the Periodic Table
p. 111

2. Understand the arrangement of the periodic table
Objectives
Understand the arrangement of the periodic table
Predict the properties of unknown elements

3. I. Organization of the Periodic Table
Mendeleev- first to arrange elements into a table
Periodic Law- similarities in properties occur in regular patterns
Arranged according to atomic number
A. Helps to determine electron configuration (p. 114) Horizontal rows, called periods, tell number of electron shells
B. Elements in the same group have similar properties Vertical columns are called groups and tell the number of valence electrons

4. Atomic Number (Z)
Symbol
Atomic Mass (A)
Electron Configuration

5. YouTube - The Elements Animation

6. II. Some atoms form ions- charged particle
A. Cations- positive ions B. Anions- negative
III. Structure of Atoms differ
A. Atomic number (Z number)- number of
protons in an element U is the largest
natural occurring element (Z=92)
B. Atomic mass (A number)- Total number
of protons and average number of neutrons
1. It is a weighted average that gives more
common isotopes more effect on the #
2. Atomic Mass Unit (AMU) – 1/12 mass of a carbon atom