The correct order of the oxidation states of nitrogen in NO, N₂O, NO₂ and N₂O₃ is :

The major product of the following reaction is :

For any given series of spectral lines of atomic hydrogen, let $$\Delta \mathop v\limits^\_ = $$ $$\Delta {\overline v _{\max }} - \Delta {\overline v _{\min }}$$ be the difference in maximum and minimum frequencies in cm^–1. The ratio Lyman Balmer $${{\Delta {{\overline v }_{Lyman}}} \over {\Delta {{\overline v }_{Balmer}}}}$$ is :

The element having greatest difference between its first and second ionization energies, is :