Question

An element 'X' has mass number 4 and atomic number 2. Find the valency of 'X'

Answer 1

• According to Bohr-Bury The electronic configuration of the element having atomic no 2 is K=2
• The maximum number of electrons that can be filed (2n²) in the K shell is two electrons.
• Since the k shell is filled completely.
• Therefore the valence of the element' X' is Zero