$Nd ^{2+}=$ ___________
Nd(60)=[Xe]4f45d06s2
Nd2+=[Xe]4f45d05s0
So, the correct option is (D): 4f4
\[ \text{Nd(60)} = [\text{Xe}] 4f^4 5d^0 6s^2 \]
For \( \text{Nd}^{2+} \), two electrons are removed (typically from the 6s orbital first):\[ \text{Nd}^{2+} = [\text{Xe}] 4f^4 5d^0 5s^0 \]
Thus, the correct answer is \( 4f^4 \).MX is a sparingly soluble salt that follows the given solubility equilibrium at 298 K.
MX(s) $\rightleftharpoons M^{+(aq) }+ X^{-}(aq)$; $K_{sp} = 10^{-10}$
If the standard reduction potential for $M^{+}(aq) + e^{-} \rightarrow M(s)$ is $(E^{\circ}_{M^{+}/M}) = 0.79$ V, then the value of the standard reduction potential for the metal/metal insoluble salt electrode $E^{\circ}_{X^{-}/MX(s)/M}$ is ____________ mV. (nearest integer)
[Given : $\frac{2.303 RT}{F} = 0.059$ V]
An infinitely long straight wire carrying current $I$ is bent in a planar shape as shown in the diagram. The radius of the circular part is $r$. The magnetic field at the centre $O$ of the circular loop is :

The scientific study of matter’s properties and behaviour is known as chemistry. It is a natural science that studies the elements that makeup matter, as well as the compounds, made up of atoms, molecules, and ions: their composition, structure, qualities, and behaviour, as well as the changes that occur when they mix with other things.