Mastering the Periodic Table

All known elements are identified and arranged in one chart called the periodic table.

History 60 different elements were discovered by 1860, by a Russian teacher named Dmitri Mendeleev. He observed that the elements with similar properties often ended up in the same column.

Arrangement The composition of substances determines the properties of those substances. In modern periodic table elements are ordered based on atomic number. This means that the elements are ordered according to the number of protons always found in an atom of that element.

Elements are substances that cannot be broken down into other substances and are made up of only one kind of atom. Today scientists have discovered 117 different elements.

Organizing the Elements The periodic table increases in atomic number across rows and down columns. The horizontal rows of the periodic table are called periods. The vertical columns on the periodic table are called groups of families. Vertical groups or families have similar physical and chemical properties.

Activity 10 Arrangement of Groups and Periods: Seeing Patterns

Reading the Periodic Table Each block includes the chemical symbol, element name, atomic number and atomic mass for each element. The Chemical symbol- one or two letters are used top abbreviate the name for each element.

Activity 16 Unusual Element Symbols