6.0

Deduce position of elements from electronic configuration.

1H : ls¹

Period l, s-block, group l

2He : ls²

Period l, s-block, group l8

Hence, helium should be placed in the s-block of Periodic table. ... As its properties are similar to the Noble gases, it is placed along with them in group 18 in p-block.

3Li : ls² 2s¹

Period 2, s-block, group l

4Be : ls² 2s²

Period 2, s-block, group 2

5B : ls² 2s² 2p¹

Period 2, p-block, group 13

C : ls² 2s² 2p² (Z=6)

Period 2, p-block, group 14

N : ls² 2s² 2p³ (Z=7)

Period 2, p-block, group 15

O : ls² 2s² 2p4 (Z=8)

Period 2, p-block, group 16