According to Mendeleev's periodic law, the elements were arranged in the periodic table in the order of-

Correct option is A

The correct answer is (a) Increasing atomic masses.
· According to Mendeleev's periodic law, elements were arranged in the periodic table based on their increasing atomic masses. Mendeleev's periodic table organized elements into rows and columns based on their chemical properties, and he observed that the properties of elements repeated at regular intervals (periodicity) when arranged by their atomic masses.
Information Booster:
· Mendeleev’s Contribution: Dmitri Mendeleev, a Russian chemist, is credited with creating the first widely recognized periodic table in 1869.
· Predictive Power: Mendeleev left gaps in his table for undiscovered elements, predicting their properties based on trends in the periodic table.
· Modern Periodic Law: The modern periodic table is arranged based on increasing atomic number, as proposed by Henry Moseley in 1913.