What is the primary characteristic by which the modern periodic table is arranged? Question 2 options: date of discovery chemical and physical properties increasing atomic mass increasing atomic number

The correct answer is: 'increasing atomic number'.

Explanation:

In the modern periodic table the elements are arranged in increasing order of their atomic numbers. An atomic number of an element represents the number of protons present in the nucleus of an atom of that element.

In modern periodic table elements are placed in 18 groups that is vertical columns and in 7 periods that is horizontal rows.

The element ins same group has similar chemical properties. Where as elements in same period has same number of energy levels or shells.

Physical properties increasing atomic number

Explanation:

The modern periodic table is arranged by the increasing atomic number and for that reason elements with similar chemical properties are in the same group