Question

Elements whose atoms have three outermost shells incomplete are called?

• A. s-block
• B. p-block
• C. d-block
• D. f-block

Answer 1

Answer: (D)

f-block

14 elements from atomic number 58 (Cerium) to 71(Lutetium) are called as Lanthanides and the another 14 elements from atomic number 90 (Thorium) to 103(Lawrencium) are called as Actinides. These 28 elements are arranged in the 2 series placed below the Modern Periodic Table and the elements in these 2 series are collectively called as f-block elements. These elements have outermost three shells incomplete. Option D is correct answer.