Species does not have a magnetic moment of 1.7 BM means species must not contain single unpaired electron.

(a) Molecular orbital configuration of O$$_2^ + $$ (15 electrons) is

$${\sigma _{1{s^2}}}\,\sigma _{1{s^2}}^ * \,{\sigma _{2{s^2}}}\,\sigma _{2{s^2}}^ * \,{\sigma _{2p_z^2}}\,{\pi _{2p_x^2}}\, = \,{\pi _{2p_y^2}}\,\pi _{2p_x^1}^ * \, = \,\pi _{2p_y^o}^ * $$

Unpaired electron = 1

$$\mu = \sqrt {n(n + 2)} = \sqrt {1(1 + 2)} = \sqrt 3 = 1.73$$

where n = no. of unpaired e^$$-$$

$$\therefore$$ $$\mu$$ = 1.73 BM

(b) Cul $$\Rightarrow$$ Cu⁺ $$-$$[Ar]3d¹⁰, Unpaired electron = 0

I^$$-$$ $$\to$$ [Xe], unpaired electron = 0

Therefore, $$\mu$$ = 0

(c) [Cu(NH₃)₄]Cl₂

Cu²⁺ $$\to$$ [Ar]3d⁹

Unpaired electron = 1,

Therefore, $$\mu$$ = 1.73 BM

(d) Molecular orbital configuration of $$O_2^ - $$ (17 electrons) is

$${\sigma _{1{s^2}}}\,\sigma _{1{s^2}}^ * \,{\sigma _{2{s^2}}}\,\sigma _{2{s^2}}^ * \,{\sigma _{2p_z^2}}\,{\pi _{2p_x^2}}\, = \,{\pi _{2p_y^2}}\,\pi _{2p_x^2}^ * \, = \,\pi _{2p_y^1}^ * $$

Unpaired electron = 1

Therefore, $$\mu$$ = 1.73 BM

Therefore, Cul does not have magnetic moment of 1.73 BM.