Modern Periodic Table

In the past, scientists believed that an element’s qualities were periodic functions of its atomic mass. Mendeleev arranged 63 elements in a vertical column named groups and horizontal rows called periods based on this idea.

This approach was disregarded since it was unable to account for the locations of several elements, rare earth metals, and isotopes. Henry Moseley, a scientist, corrected these flaws and proposed the modern periodic table and periodic rule.

Modern Periodic Law

The physical and chemical properties of elements are the periodic function of their atomic numbers.
Cause of periodicity – It is due to the repetition of the same outer shell electronic configuration at a certain regular interval.

Features of Modern Periodic Table

The vertical columns and horizontal rows that make up the long version of the periodic table are called groups and periods, respectively.

• According to their increasing atomic numbers, elements are organised.
• The contemporary periodic table divides the elements into 7 periods and 18 groups.
• Vertical columns are known as groups, and horizontal rows are known as periods.
• Depending on how many atomic shells each element has, it is classified into periods.
• The first period, which only has two elements—hydrogen and helium—is the shortest.
• The sixth period in the periodic table is regarded as the longest period. It contains substances ranging from Radon to Cesium.
• The seventh period is a blank period.
• Actinides and Lanthanides are included at the bottom of the periodic table.