The periodic table shows the elemental similarity, and through it it is possible to know the properties of an element based on a member belonging to the same family or group. Look at Group 2 of the periodic table and see why the members are located close together:
Atomic No. Element Electronic Configuration
4 B and 2 s2
12 mg 3 s2
20 Ca 4 s2
38 Mr 5 s2
56 Ba 6 s2
88 Ra 7 s2
Note: This setting is equivalent to the last sublevel that received electrons.
Group 2 A, also called the Earth Alkaline family, comprises metals with electronic distribution ending in sublevel s2. Although the atomic numbers of the elements are different, the number of electrons in the valence shell is the same, and corresponds to 2. The electronic configurations of these elements are similar and therefore chemically similar, this leads us to the Periodic Law:
"The physical and chemical properties of elements are periodic functions of their atomic numbers."
table structure
In the table, the elements are arranged horizontally, in numerical sequence, according to their atomic numbers, resulting in the appearance of seven horizontal lines (or periods). Each period, with the exception of the first, begins with a metal and ends with a noble gas. The periods differ in length, with some having only 2 elements (short period) and others already have 32 elements (long period).
The groups correspond to the vertical lines, which have been grouped based on the similar structures of the outer layer (as in the example of group 2). In some of these groups, the elements are so closely related in their properties that they are called families, for example, group 1 A is the Alkaline Metals family.
By Líria Alves
Graduated in Chemistry
Source: Brazil School - https://brasilescola.uol.com.br/quimica/organizacao-tabela-periodica.htm
