Question

Mendeleev's Modren periodic law is based on :

• A. Atomic mass
• B. Atomic Number
• C. No. of Nutron's
• D. Atomic mass and atomic Number

Hint:

Remember the key distinction: Mendeleev's original periodic law is based on atomic mass, while the Modern Periodic Law is based on atomic number.

Answer 1

The Correct Option is A

Step 1: Understand Mendeleev's original Periodic Law.
Dmitri Mendeleev formulated the periodic law stating that the properties of elements are a periodic function of their atomic masses. He arranged elements in his periodic table primarily based on increasing atomic mass. Step 2: Differentiate between Mendeleev's and the Modern Periodic Law.
The question specifically asks about "Mendeleev's Modren periodic law". This phrasing is slightly ambiguous. The "Modern Periodic Law" (as established later by Moseley) is based on atomic number. However, if it refers to "Mendeleev's" law, it is based on atomic mass. Given the options, it's highly likely it refers to Mendeleev's original formulation. Step 3: Evaluate the given options.

(1) Atomic mass: This is the basis of Mendeleev's original periodic law.
(2) Atomic Number: This is the basis of the Modern Periodic Law (developed after Mendeleev's work).
(3) No. of Nutron's (Neutrons): The number of neutrons (and thus mass number) is related to atomic mass, but Mendeleev didn't explicitly use neutron count as the basis.
(4) Atomic mass and atomic Number: While both are important properties, Mendeleev's law was specifically based on atomic mass. Step 4: Conclude the correct basis for Mendeleev's periodic law.
Mendeleev's periodic law is based on atomic mass. (1) Atomic mass