$A$ compound absorbs light in the wavelength region $490-500 \,nm$. Its complementary colour is

What is the magnetic moment value of $Ni^{2+}$ in an aqueous solution in Bohr Magnetons? (Atomic number: $Ni = 28$)

$A$ compound of a metal ion $M^{x+}$ $(Z = 24)$ has a spin-only magnetic moment of $\sqrt{15} \ BM$. The number of unpaired electrons in the compound is:

The coordination number,oxidation number,number of electrons in $d$-orbital,and number of unpaired electrons respectively in the complex $[Co(NH_3)_4CO_3]ClO_4$ are . . . . . . .

The spin-only magnetic moments of $[Fe(NH_3)_6]^{3+}$ and $[FeF_6]^{3-}$ in $BM$ are,respectively

The electronic configurations of $Cr^{2+}, Mn^{2+}, Fe^{2+},$ and $Co^{2+}$ are $d^4, d^5, d^6,$ and $d^7$ respectively. Which of the following has the lowest magnetic moment? $[Cr = 24, Mn = 25, Fe = 26, Co = 27]$