Question

Modern Periodic Law.

Answer 1

Modern Periodic Law 

✌️✔️In the year 1913 A.D, An English scientist Henry Moseley demonstrated, with the help of experiments done using X-ray tube , that the atomic number ( Z ) of an element corresponds to the positive charge on the nucleus or the number of the protons in the nucleus of an atom. 

✌️✔️This revealed that "Atomic number" is a more fundamental property of an element than it's atomic mass.

✌️✔️Thus, Accordingly, the statement of the modern periodic law was stated as follows :-

✌️✔️" Properties of elements are a periodic function of the atomic numbers. " 

Answer 2

1. Firstly Moseley gives the law in 1942 which is generally based on atomic number.

2. It states that the physical and chemical properties of the elements are periodic functions of their atomic numbers.

3. As there are seven periods and also nine groups in this table, including the group which is generally known as zero group.

4. The 2nd and 3rd periods are called the short period as it contains only 8 elements in each period.

5. 1st period is known as short period as it contains only 2 elements