Question

Newland’s octave theory was based on atomic weight while Julius Lothar Meyer's classification was based on valence of elements. Is the mendeleev’s periodic table based on atomic weight or valence?

Answer 1

Hint: Before answering this, we should know what the periodic table is. The arrangement of elements in a tabular form, the categorization of elements according to their properties is known as the periodic table. 118 elements are present in our periodic table in which 94 elements are natural elements and 24 elements are synthetic elements.

Complete answer:
The British chemist named John Newland in the year 1864 achieved 62 elements which were known at that time. All the elements were arranged in ascending order according to their atomic masses and made an observation that every eighth element has similar properties. Newland’s law of octaves was formulated based on this observation.
The law of octaves states that “Every eighth element has similar properties when the elements are arranged in the increasing order according to their atomic masses.”

Newlands gave a concept where he compared the elements to the octaves of music in which every eighth note is similar to the first. Every element was assigned an atomic number in this attempt. However, This method of classifying elements was not completely accepted by the scientific community.
The arrangement of elements according to the increase of their atomic weights is Mendeleev’s periodic table. Here, the priority was the properties of the elements. The elements of similar chemical properties have the same valences in the hydrides and oxides.

Note:
Mendeleev Periodic table: Only 30 elements were known in the year 1800. AS the elements kept on discovering, it became a headache for scientists to remember the properties of all the elements individually. They started categorizing elements according to the properties of them. This became a popular concept.