Periodic Table and Element Properties
Learn about the categorization of various elements into groups and periods according to the similarities and differences in their properties. Metals, metalloids, and non-metals are organized separately.
TABLE OF CONTENTS Periodic Table and Element Properties
Chapter 1: Periodic Table and Element Properties
The modern periodic table sorts all chemical elements in a logical way based on their atomic numbers. The periodic table correlates the atomic structure of each element with its position in the table. It also reflects the similarities, differences, and trends in the physical and chemical properties of the elements in a systematic way.
The modern periodic table is based on the periodic law, which states that physical and chemical properties of the elements are a periodic function of their atomic numbers.
Evolution of the Periodic Table
In 1829, Doberenier made the first attempt to link the chemical properties of elements with their atomic weights. He proposed a law of triads, which states that in certain triads, the atomic mass of the central element is the arithmetic mean of the atomic masses of the other two elements. This theory collapsed when it was found that in some triads, all three elements possess the same atomic mass.
In 1864, John Newlands proposed a law of octaves, which states that every eighth element has similar chemical properties. This theory too failed to withstand scientific scrutiny and the law was denied for acceptance.
In 1869, Mendeleeff classified elements, based on their chemical properties. He proposed that the properties of elements were a periodic function of their atomic masses. Mendeleeff's periodic table suffered from many defects. For example, it could not specify the positions of isotopes, lanthanides, and actinides. To remove these defects, many new tables were proposed, the best of which is the...
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