Question

Differentiate between the arrangement of elements in mendeleev periodic table

and modern periodic table.

Q16.(a) Write joules law of heating

(b) two lamps one rated 100 watt 2​

Answer 1

☆ Mendeleev's periodic table

• Elements are arranged in increasing order of their atomic masses.
• Positions of isotopes are not justified.
• The position of hydrogen was not justified.

☆ Modern periodic table

• Elements are arranged in increasing order of their atomic numbers. 
• Isotopes occupy definite Position.
• Hydrogen has given definite position.