Question

Do elements that have many similar properties belong to the same period or group on the periodic table?

Answer 1

The modern periodic table is arranged according to the increase in atomic number. The horizontal column is known as the period and the vertical rows are known as groups. There are eight periods and eighteen groups in the modern periodic table.

Complete Step By Step Answer:
The elements that fall below to each other come under one group. There are 18 groups in the periodic table. As we move down the group, the elements present are considered as one family. There are different groups present, example alkaline metals (group I), alkaline earth metals (group II), halides (group XVII) and halogen (group XVIII)
The elements in one group, if we move from down the group, are arranged in increasing atomic number and size. The thing that is common is the number of valence electrons in the shell. For example, group I elements have one electron in the outermost orbital. Hence the valency is 1. Also, the electronic configuration is similar i.e. $n{s^1}$. Because of this their properties also tend to be very similar. All of the group I elements are soft and can be cut with a knife, they have low melting and boiling points, all of them form basic oxides, etc.
Therefore, elements that have many similar properties belong to the same group on the periodic table.

Note:
There are many exceptions for the elements belonging to the same group, having similar properties. The atomic size doesn’t increase as we move down the group in transition metal elements. The elements belonging to the same period have huge variations in their properties, as they have different valence electrons and also configurations.