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 lanthanides and only 14 actinides in Modern periodic table.
Text Solution
Verified by ExpertsCHECK THE SOLUTION.
(i) In modern periodic table, elements have been placed in order of their increasing atomic numbers. The atomic number of argon is 18 and that of potassium is 19. Thus, argon has been placed before potassium.
(ii) In lanthanides and actinides, the differentiating electron enters to (n – 2) f-subshell. The maximum capacity of f-subshell is of 14 electrons. Thus, there are only 14 lanthanides (4f 1–14 ) and only 14 actinides (5f 1–14 ).
Prepare Smarter with CGP Edu
Get practice questions, solutions, and test series in one place.
Write a Review
Share your experience with this question and solution.
Commentary
Send your comment, doubt, correction, or feedback to admin.
Similar Questions
Explore conceptually related problems