Question

Name the scientist who first of all showed that the atomic number of an element is a more fundamental property than its atomic mass.

Answer 1

Here we are asked to name the scientist who first discovered that the atomic number of an element is a more fundamental property in comparison to its atomic mass. Recall that, initial studies about the discovery of various elements and their properties were based on their atomic masses.

Complete step by step solution:
The Modern periodic law, ‘Properties of elements are a periodic function of their atomic number’ was proposed based on the idea of Henry Mosely that the atomic number of an element is a fundamental property of an element rather than its atomic mass.
Before the advent of the Modern Periodic Table, most of the scientists tried to correlate the properties of elements with their atomic masses and not the atomic number. There were many limitations to this idea of classification of elements.

Hence, the answer is Henry Moseley.

Additional Information:
Some of the limitations of Mendeleev’s periodic table were overcome with the new idea of classification of elements based on atomic numbers proposed by Henry Mosely.
1.An anomalous position was assigned to hydrogen in the periodic table.
2.Isotopes of the same element do not have separate positions in the modern periodic table. One element occupies only one position in the periodic table, because isotopes have the same atomic number but only different mass numbers.

Note: Understand the difference between atomic number and atomic mass. Atomic number of an element is the total number of protons present in the nucleus of an element whereas, atomic mass of an element is the sum of the total number of neutrons and protons present in the nucleus of an element.