Question

5 differences between mendeleev's table and modern periodic table of henry mosley ​

Answer 1

Differences between mendeleev's table and modern periodic table of Henry Moseley:

• Mendeleev periodic table has chemical elements arranged on the basis of atomic mass.
• Modern periodic Table has chemical elements based on atomic number.

• Mendeleev periodic table has 63 elements.
• The modern periodic table has 118 elements.

• In Mendeleev periodic table, transition elements are also included with other elements.
• In modern periodic Table transition elements are placed in separate block. [ Showing them in main body of the table will distort the shape of the periodic table ]

• In Mendeleev periodic table, there was some gaps left behind for subsequent inclusion of elements not known that time.
• In modern periodic Table, do not have such gaps because different elements have different atomic number.

• There were no noble gases in Mendeleev periodic table because the noble gases was not discovered at that time.
• In modern periodic Table, noble gases have placed in group number 18.

Answer 2

Mendeleev's table :-

1. Did the arrangement in 1869.
2. Arranged the elements in increasing order of their atomic weights in the form of a table and called it the periodic table.
3. Noticed that elements with similar properties, appear at regular intervals.
4. And this is named as periodicity of properties of elements.
5. Stated that properties of elements are periodic functions of their atomic weights.

Mosely's table :-

1. Did the arrangement in 1912.
2. Arranged the elements in increasing order of their atomic numbers.
3. Said that atomic number is a more fundamental characteristic of an element than its atomic weight.
4. Stated that properties of elements are periodic functions of their atomic numbers.
5. This is the modern periodic table and followed by everyone.