Question

What were the limitations of Mendeleev's periodic table?

• A. Position of hydrogen
• B. Position of isotopes
• C. Similar elements placed separately
  
• D. Blank spaces for undiscovered elements

Answer 1

Answer: (A), (B), (C)

Similar elements placed separately


Mendeleev's periodic table had the following limitations: Hydrogen was placed in group 1A with alkali metals, but certain properties of hydrogen resemble those of halogens. Isotopes were not given separate places in the periodic table because of their similar properties. Also, some similar elements were placed separately in Mendeleev's periodic table. For example, chemically similar elements like copper and mercury were placed in different groups.