To which block does the element with atomic number $106$ belong?

List the elements of the first transition series.

Pair of transition metal ions having the same number of unpaired electrons is $:$

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:

Identify the outer electronic configuration of the $first$ element of the $first$ transition series.

Which metal is present in brass,bronze and German silver?