Periodic table of the elements
The periodic table, as we know it today, is an array of the elements arranged in order of increasing atomic number. When the elements are arranged in order of increasing atomic number, the physical and chemical properties of the elements vary periodically at regular intervals. This relationship is known as the periodic law.
There are seven periods of elements in the periodic table.
Each period has a variation in physical and chemical properties. It starts with reactive metals on the left side and ends with the nonreactive noble gas on the right side.
The number of the period gives the number of the outermost principal energy level that the valence electron(s) occupies. This is best illustrated by reviewing the arrangement of electrons in principal energy levels and the Bohr diagrams.
There are 18 vertical columns of elements in the periodic table. Each column is called a group of elements, or a family of elements. Elements in the same family or group tend to have similar properties.
There are two formats in labeling the groups on the periodic table. In some books (and on the Internet) you will find the "1-18" numbering sequence. In other books, you will find the more popular "1-8 A and B" group labeling system. In this course, we will use the latter system of labeling.
|"A" elements||The Representative Elements||Group IA|
Noble gases or Inert gases
BCIT courses: CHEM 0011