How does the modern periodic table arrange elements?

The elements are arranged according to the atomic numbers.

Explanation:

Elements in a periodic table are distributed in 7 Periods and 18 Groups.

The elements are distributed on the basis of increasing atomic numbers. They are arranged horizontally with increasing atomic number.

In earlier times, the periodic table was arranged according to average atomic mass which had many anomalies.

When elements are arranged according to atomic numbers, they followed a periodic pattern and thus similar elements can be categorized in the same group.

Thus, in modern periodic table, the elements are arranged according to increasing atomic numbers.