$A$ substance contains an $M^{3+}$ ion with the electronic configuration $[Ar]3d^1$. The ion is........

The atomic number of an element is $26$. The element shows:

Explain the exceptions in the general electronic configuration of $3d$-series elements.

An element with atomic number $21$ is a

In the first transition series,the metallic bond strength increases from ..... to .....

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A)$: The first ionization enthalpy of $3d$ series elements is more than that of group $2$ metals.
Reason $(R)$: In $3d$ series of elements,successive filling of $d$-orbitals takes place.
In the light of the above statements,choose the correct answer from the options given below: