Question

Which is not s–block element ?

• A. [Ar]4s23d104p65s1
• B. 1s2 2s22p1
• C. [He] 2s22p63s1
• D. None of these

Answer 1

Answer: (B)

1s2 2s22p1

Answer 2

The block of an element depends on the type of sub-shell which receives the last electron. As last electron enters in p-subshell of outer most shell according to Aufbau rule, the element of option (2) belongs to p-block.