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

The hardness of interstitial compounds is comparable to which of the following?

Elements of $d$-block are called

The correct order of decreasing third ionisation enthalpy of $Ti$,$V$,$Cr$,and $Mn$ is:

Assertion $(A)$: While going from left to right in the periodic table,the atomic size decreases more rapidly for the $3d$-series compared to the $4f$-series of elements.
Reason $(R)$: $3d$-electrons experience lesser shielding than $4f$-electrons.

Which of the following statements is not correct? $(Ve = 58, \, Lu = 71, \, La = 57, \, Yb = 70)$