$d-d$ transition occurs in . . . . . . .

How many of the following metal ions have similar values of spin-only magnetic moment in the gaseous state?
(Given: Atomic number: $V, 23; Cr, 24; Fe, 26; Ni, 28$)
$V^{3+}, Cr^{3+}, Fe^{2+}, Ni^{3+}$

The calculated magnetic moment (in Bohr magnetons) of $Cu^{2+}$ ion is:

Which element is named after the name of a planet?

Which of the following does not represent the property stated against it?

The correct statement$(s)$ about $Cr^{2+}$ and $Mn^{3+}$ is(are)
[Atomic numbers of $Cr = 24$ and $Mn = 25$]
$(A)$ $Cr^{2+}$ is a reducing agent
$(B)$ $Mn^{3+}$ is an oxidizing agent
$(C)$ Both $Cr^{2+}$ and $Mn^{3+}$ exhibit $d^4$ electronic configuration
$(D)$ When $Cr^{2+}$ is used as a reducing agent,the chromium ion attains $d^3$ electronic configuration