D And F Block Elements Question 266
Question: Lanthanoids are
[CBSE PMT 2004]
Options:
A) 14 elements in the sixth period (atomic no. = 58 to 71) that are filling 4f sublevel
B) 14 elements in the seventh period (atomic no. = 58 to 71) that are filling 4f sublevel
C) 14 elements in the sixth period (atomic no. = 90 to 103) that are filling 4f sublevel
D) 14 elements in the seventh period (atomic no. = 90 to 103) that are filling 4f sublevel
Show Answer
Answer:
Correct Answer: A
Solution:
As sixth period can accommodate only 18 element in the table, 14 member of HF series (atomic number 58 ot 71) are separately accommodated in a horizontal row below the periodic table.
These are called as lanthanides.
BETA
