The electronic configuration of an element is 1s², 2s² 2p⁶, 3s² 3p⁶ 3d⁵, 4s¹ This represents its

Amongst the following identify the species with an atom in +6 oxidation state

The number of nodal planes in a p_x orbital is

Amongst H₂O, H₂S, H₂Se and H₂Te, the one with the highest boiling point is