Answer question numbers `(a) - (d)` on the basis of your understanding of the following paragraph and related studied concepts.
In 1913, Henry Moseley showed that the atomic number (symbolised as Z) of an element is a more fundamental property than its atomic mass. Accordingly, Mendeleev's Periodic Law was modified and atomic number was adopted as the basis of Modern Periodic Table and the Modern Periodic Law can be stated as follows :
'Properties of elements are a periodic function of their atomic number.' Let us recall that the atomic number gives us the number of protons in the nucleus of an atom and this number increases by one in going from one element to the next. Elements, when arranged in order of increasing atomic number, lead us to the classification known as the Modern Periodic Table. Prediction of properties of elements could be made with more precision when elements were arranged on the basis of increasing atomic number.
(b) What is Modern Periodic Law ?

Explanation

Modern Periodic Law states that properties of elements are a periodic function of their atomic numbers.