The total number of anti bonding molecular orbitals, formed from $$2 s$$ and $$2 p$$ atomic orbitals in a diatomic molecule is _______.

The half-life of radioisotope bromine - 82 is 36 hours. The fraction which remains after one day is ________ $$\times 10^{-2}$$.

(Given antilog $$0.2006=1.587$$)

The total number of 'Sigma' and 'Pi' bonds in 2-formylhex-4-enoic acid is _________.

The oxidation number of iron in the compound formed during brown ring test for NO$$_3^-$$ iron is ________.