Question

What are periods in a periodic table?
What is meant by period number? What does it signify?

Answer 1

Hint: In order to solve the problem given above first we will understand the basic definition and the arrangement mechanism in a periodic table. We will also understand the reason behind and the advantages of such arrangements with simple examples. Further we will see the basic definitions related to the periodic table and also the definition of periods and the meaning of period number as well as the significance of period number.

Complete step by step answer:
In accordance with their increasing atomic number and repeated chemical properties, the periodic table is an arrangement of all the elements known to man. In a tabular arrangement in which a row is a time and a column is a group, they are assorted.
A new and updated iteration of some versions put out by scientists in the 19th and 20th centuries is the modern periodic table, the one we have today. Centered on the observations of several scientists before him, such as John Newlands and Antoine-Laurent de Lavoisier, Dimitri Mendeleev proposed his periodic table. However, for his invention of the periodic table, Mendeleev is given sole credit.
Elements are grouped in the order of their increasing atomic numbers, from left to right and top to bottom. Accordingly,
Elements in the same group may have the same structure of the valence electron and hence identical chemical properties.

Whereas, elements would have a growing order of valence electrons in the same time. Therefore, as the atom's energy level grows, the amount of sublevels of energy per level of energy grows.
The horizontally arranged each row in the table are the periods of the periodic table in which certain elements are arranged with increasing atomic number from left to right.
The periodic number can be seen as the row number of the periodic table.
The similarity between these elements is they all have the same number of atomic orbital which is equal to the period number of the element.
Let us see this by an example
“Li”, “Be” and “B” belong to the second period of the periodic table. This means that each of these elements has only 2 atomic orbital for their electron.

Note: In order to solve such types of problems students must remember different types of periodic tables that were proposed and the developments made in each one and also the characteristics and the features of the modern periodic table. Also the students must know about the relation between the elements which lie in the same vertical column or the group of periodic tables.