(a) What were the two major shortcomings of Mendeleev's periodic table? How have these been removed in the modern periodic table?(b) Two elements X and Y have atomic numbers 12 and 16 respectively. Write the electronic configuration for these elements. To which period of the modern periodic table do these two elements belong? What type of bond will be formed between them and why?(c) To which groups of the modern periodic table do the elements X and Y belong? Give reason for your answer.(d) What could the elements X and Y be? Write their names and symbols.

(a) What were the two major shortcomings of Mendeleev's periodic table

1.	(a) What were the two major shortcomings of Mendeleev's periodic table? How have these been removed in the modern periodic table?(b) Two elements X and Y have atomic numbers 12 and 16 respectively. Write the electronic configuration for these elements. To which period of the modern periodic table do these two elements belong? What type of bond will be formed between them and why?(c) To which groups of the modern periodic table do the elements X and Y belong? Give reason for your answer.(d) What could the elements X and Y be? Write their names and symbols.
Answer» (a) What were the two major shortcomings of Mendeleev's periodic table? How have these been removed in the modern periodic table? (b) Two elements X and Y have atomic numbers 12 and 16 respectively. Write the electronic configuration for these elements. To which period of the modern periodic table do these two elements belong? What type of bond will be formed between them and why? (c) To which groups of the modern periodic table do the elements X and Y belong? Give reason for your answer. (d) What could the elements X and Y be? Write their names and symbols.