Explain the following:
(i) Why argon (atomic mass `= 39.94)` has been placed before potassium (atomic mass `= 39.10)` in the Modern periodic table?
(ii) There are only `14` anthanides and only `14` actinides in Modern peridoic table.

Why Ar (argon) (at, wt. = 39.94 ) has been placed before K (at. Wt. = 39.10 ) in the periodic table?

Why Ar (argon) (at, wt. = 39.94 ) has been placed before K (at. Wt. = 39.10 ) in the periodic table?

Which of the following statement (s) about the Modern Periodic Table is are incorrect (i) The elements in the Modern Periodic Table are arranged on the basis of their decreasing atomic number (ii) The elements in the Modern Periodic Table are arranged on the basis of their increasing atomic masses (iii) Isotopes are placed in adjoining group (s) in the Periodic Table (iv) The elements in the Modern Periodic Table are arranged on the basis of their increasing atomic number