Question

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Helium atom has 2 electrons in its valence shell but its valency is not 2. Explain.

Answer 1

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Helium has 2 electrons in its outermost shell thereby completing duplet configuration. Hence it has no valence shell left empty making its valency 0.