The hydrogen like species Li²⁺ is in a spherically symmetric state S₁ with one radial node. Upon absorbing light the ion undergoes transition to a state S₂. The state S₂ has one radial node and its energy is equal to the ground state energy of the hydrogen atom.

The orbital angular momentum quantum number of the state S₂ is

Among the following, the number of elements showing only one non-zero oxidation state is :
O, Cl, F, N, P, Sn, Tl, Na, Ti

Assuming that Hund’s rule is violated, the bond order and magnetic nature of the diatomic molecule B₂ is

The total number of diprotic acids among the following is:

H₃PO₄, H₂SO₄, H₃PO₃, H₂CO₃, H₂S₂O₇, H₃BO₃, H₃PO₂, H₂CrO₄ and H₂SO₃