Which of the following ions or atoms possess paramagnetic properties ? zn s2- ar+ s co

Ar⁺, S and Co are paramagnetic in nature

Explanation:

Paramagnetism is a property of a given chemical substance and it is due to the presence of unpaired electrons.

Zinc (Zn)-

Electron configuration in ground state- Zn: [Ar] 3d¹⁰4s²

Since the transition metal zinc has completely filled (n-1)d and ns orbital.

Therefore, the number of unpaired electrons = 0

⇒ Zn is not paramagnetic

Sulphide (S²⁻)- anion of sulfur

Reduction reaction: S + 2e⁻ → S²⁻

Electron configuration in ground state- S: [Ne] 3s²  3p⁴

Electron configuration in excited state- S²⁻ : [Ne] 3s²  3p⁶

Since sulfide ion, S²⁻ has completely filled ns and np orbitals.

Therefore, the number of unpaired electrons = 0

⇒ S²⁻ is not paramagnetic

Ar⁺- cation of argon

Oxidation reaction: Ar → Ar⁺ + e⁻

Electron configuration in ground state- Ar: [Ne] 3s²  3p⁶

Electron configuration in excited state- Ar⁺ : [Ne] 3s²  3p⁵

Since Ar⁺ has completely filled ns orbital and 5 electrons in np orbital.

Therefore, the number of unpaired electrons = 1

⇒ Ar⁺ is paramagnetic

Sulfur (S)-

Electron configuration in ground state- S: [Ne] 3s²  3p⁴

Since S has completely filled ns orbital and 4 electrons in the np orbital.

Therefore, the number of unpaired electrons = 2

⇒ S is paramagnetic

Cobalt (Co)-

Electron configuration in ground state- Co: [Ar] 3d⁷ 4s²

As, the transition metal cobalt has completely filled ns orbital and 7 electrons in the (n-1)d orbital.

Therefore, the number of unpaired electrons = 3

⇒ Co is paramagnetic