Question

which is the correct statement of the periodic law? *
\when elements are arranged by increasing atomic mass properties repeat regularly\
\when elements are arranged by increasing atomic number properties repeat regularly\
\when elements are arranged by increasing atomic mass properties repeat irregularly\
\when elements are arranged by increasing atomic number properties repeat irregularly\

Explanation:

The Periodic Law states that when elements are arranged in order of increasing atomic number, their chemical and physical properties repeat periodically (regularly). Arranging by atomic mass had inconsistencies (like with isotopes or some element pairs), and properties don't repeat irregularly. So the correct statement is the one about arranging by increasing atomic number with regular repetition of properties.

Answer:

B. "When elements are arranged by increasing atomic number properties repeat regularly"