Question

Helium has a electronic configuration of 1$s^{2}$ but it is placed in p-block in group 18. Explain.

Answer 1

The electronic configuration of helium is $1s^{2}$ but it is placed in group 18 because it is a non-metallic gas and its physical & chemical properties are similar to that of the group 18 elements. So, it is placed in p-block elements. These group elements are termed as noble gases.

They have a completely filled electronic configuration and have zero valence electron.

By possessing such a configuration, they tend to be highly stable.

Answer 2

The electronic configuration of helium is 1s^{2}1s2 but it is placed in group 18 because it is a non-metallic gas and its physical & chemical properties are similar to that of the group 18 elements. So, it is placed in p-block elements. These group elements are termed as noble gases.

They have a completely filled electronic configuration and have zero valence electron.

By possessing such a configuration, they tend to be highly stable.