The Periodic Table Its development and structure

Dimitri Mendeleev

The First Published Periodic Table Dimitri Mendeleev was the first person to publish an organization of the elements. 1894

Other scientists had noticed repeating properties in the elements. Mendeleev took the 64 known elements and placed them in 8 columns according to atomic mass. When he came to an element that had similar properties to another, he placed them together.

Mendeleev left blanks where no element existed and predicted that an element would be found that had the mass and properties to fit there. He correctly predicted the existence of silicon, aluminum and gallium

Periodicity in the Table The most important part of the Periodic Table is that it shows the trends of the properties of the elements. These are the properties such as: metallic properties, atomic radius, ionization energy

Structure of the Periodic Table There are three types of elements on the periodic table: metals, non-metals and metalloids Metals are found on the left side of the zig-zag line. Non-metals are found on the right side of the zig-zag line Metalloids are found on the zig-zag line

Horizontal rows are called periods Vertical columns are called groups or families Structure of the Periodic Table

Families or groups on the Periodic Table Elements that are in the same family or group have similar physical and chemical properties. It was these properties that Meldeleev used to create the table.

Some families have names: Alkali Metals Alkaline Earth Metals Halogens Noble Gases

Symbols on the Periodic Table All of the elements on the periodic table have symbols to represent them. These symbols are the same ones used all over the world. Each symbol is either an upper case letter OR an uppercase letter followed by a lower case letter Ex.: H, He, C, Cl

Symbols on the Periodic Table The symbols are often the first letter of the name of the element or the first two letters. C is carbon He is helium The symbols may be the first letters of the name of the element in a language other than English. Iron is Fe for ferrous Lead is Pb for plumbum