Among the triatomic molecules/ions, BeCl₂, $$N_3^-$$, N₂O, $$NO_2^+$$, O₃, SCl₂, $$ICl_2^-$$, $$I_3^-$$ and XeF₂, the total number of linear molecule(s)/ion(s) where the hybridization of the central atom does not have contribution from the d-orbital(s) is

[Atomic number: S = 16, Cl = 17, I = 53 and Xe = 54]

A list of species having the formula XZ₄ is given below.

XeF₄, SF₄ ,SiF₄, $$BF_4^-$$, $$BrF_4^-$$, [Cu(NH₃)₄]²⁺, [FeCl₄]^2-, [CoCl₄]^2- and [PtCl₄]^2-

Defining shape on the basis of the location of X and Z atoms, the total number of species having a square planar shape is

Based on VSEPR theory, the number of 90 degree F-Br-F angles in BrF₅ is

There are ______ $$\pi$$ bonds in a nitrogen molecule.