Question

periodic table high school reference sheet
the periodic law states that:
a. the periodic table arranges elements into periods and groups.
b. the properties of elements recur periodically based on their metallic qualities.
c. the properties of elements recur periodically when arranged by increasing atomic mass.
d. the properties of elements recur periodically when arranged by increasing atomic number.

Explanation:

The periodic law is a fundamental concept in chemistry. It was initially thought to be based on atomic mass (Mendeleev's work), but with the discovery of atomic number (by Henry Moseley), the modern periodic law is defined as the properties of elements recurring periodically when arranged by increasing atomic number. Option A just describes the structure of the periodic table, not the law. Option B is incorrect as it mentions metallic qualities which is not the basis. Option C was an older, less accurate version.

Answer:

D. The properties of elements recur periodically when arranged by increasing atomic number.