Question

Que-1 (5 marks)
a)The modern periodic table has been evolved through the early attempts of Dobereiner , Newland and Mendeleev. List one advantage and one limitation of all the three attempts.
b)Name the scientist who first of all showed that atomic number of an element is a more fundamental property than it's atomic mass.
C) state modern periodic law
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Answer 1

Answer:

a).Dobereiner gave an idea of classification of elements in the form of triads. Limitation: He could not able to arrange all element present that time. Newland: Newland arranged elements in order of increasing atomic mass and encouraged other chemists to corrleate the properties of elements with their atomic masses.

a).Dobereiner gave an idea of classification of elements in the form of triads. Limitation: He could not able to arrange all element present that time. Newland: Newland arranged elements in order of increasing atomic mass and encouraged other chemists to corrleate the properties of elements with their atomic masses.c).The modern periodic law states that the properties of elements are a periodic function of their atomic numbers. ... (c) When the elements are arranged according to their atomic numbers on the basis of modern periodic law, then all the anomalies (or defects) of Mendeleev's classification disappear.

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