Which of the following series of transition elements has the general electronic configuration $[Kr] 4d^{1-10} 5s^{0-2}$?

How do the oxidation states of the elements vary in the transition series?

Besides $Zn$ and $Cu$,german silver contains the metal

Match the column-$I$ with column-$II$.

column-$I$ $(\text{Property})$	column-$II$ $(\text{Metal})$
$i$. An element which can show $+8$ oxidation state	$a$. $Mn$
$ii$. $3d$ series element that can show upto $+7$ oxidation state	$b$. $Cr$
$iii$. $3d$ series element with highest melting point	$c$. $Os$

Number of paramagnetic ions among the following $d$- and $f$-block metal ions is . . . . . . . $Mn^{2+}$, $Cu^{2+}$, $Zn^{2+}$, $Yb^{2+}$, $Sc^{3+}$, $La^{3+}$, $Gd^{3+}$, $Lu^{3+}$, $Ti^{4+}$, $Ce^{4+}$. (Atomic number of $Mn = 25$, $Cu = 29$, $Zn = 30$, $Yb = 70$, $Sc = 21$, $La = 57$, $Gd = 64$, $Lu = 71$, $Ti = 22$, $Ce = 58$)

Fill in the blanks:
$(a)$ The $4f$ and $5f$ series elements are known as lanthanoids and actinoids,respectively.
$(b)$ In transition elements,electrons are filled in the $d$-orbitals of the .......... energy levels.