Configuration of d-block elements.. is (n-1)d^1to10ns^1to2..
but, as these are d-block elements.. and last electron should enter into d subshell.. so, shouldn't it be..​ (n-1)d^1to10ns².. ?!

 Dear Student,
The electronic configuration of d-block elements is $(n-1)d^{1-10}n{s}^2$
The filling of electrons takes place in accordance with afbau principle.
According to afbau principle the electrons are filled in increasing order of energy,  In the 3d transition series the 4s subshell has a lower energy than the 3d subshell thats why first the electron goes into 4s then 3d. 

The configuration is written as $(n-1)d^{1to 10}n{s}^{1 to 2}$
ns^{​1 to 2} is written because in certain metals due to the extra stability of half filled subshell one electron moves to d -subshell. 
For example in Cu and Cr
Regards!