Question

In long form of periodic table, the properties of the elements are a periodic function of their:
A) Atomic size.
B) Ionization energy
C) Atomic mass.
D) Atomic number.

Answer 1

Hint:Now we see the modern periodic law:
The periodic functions such as the Physical and chemical properties of the elements depend on the atomic numbers of a component.
Complete step by step answer:First, we see Mendeleev periodic law:
The physical and chemical properties of the elements are the periodic function depending on the atomic mass of an element.
Let us see the restrictions of Mendeleev’s table.
Limitations of the Mendeleev table are listed below.
Elements with large differences in properties were included within an equivalent group. As an example, hard metals like copper and silver were included alongside soft metals like sodium and potassium.
There is no proper position to the element hydrogen. Within the table, things of hydrogen are uncertain. It had been put with alkali metals within 1A class, but certain hydrogen properties are almost those of halogens. So, it can also be put for halogens within the band.
As isotopes are atoms of the same element having different atomic masses, they need to tend different positions while arranging them within the order of mass. But this wasn't done.
Modern periodic law could even be stated that the physical and chemical properties of elements are the periodic functions of their atomic numbers. Elements are arranged according to increasing atomic numbers. Elements with similar properties are placed together.

Therefore, the option D is correct.


Note: Mendeleev's table is widely accepted mainly because he identified the characteristics and placement of elements that need to be discovered and he left spaces within the table to put the elements.
The modern table different from Mendeleev’s periodic table in the following ways,
1. Moseley realized that number is the elemental property of a component rather than its weight.
2. He arranged the elements within the table according to their atomic numbers.
3. This arrangement removes the matter of atomic weights.
4. Within the modern table, isotopes are put alongside their elements.