Chapter 5: The Periodic Table

Video

Section 1: Organizing the Elements

Video 2

Recognizing a Pattern

• Dmitri Mendeleev:– In this periodic table,

Mendeleev arranged elements in rows by increasing atomic mass

– He was able to predict new elements

– Few elements did not fit the pattern

Changing the Arrangement

• The modern periodic table organizes elements by atomic number. When the elements are arranged in this way, elements that have similar properties appear at regular intervals.

• Elements become less metallic across each period (each row of the table is a period)

• Elements in a group have similar properties (each column of the periodic table is a group)