Question

what is the last portion of the electron configuration for technetium, tc?
$5d^{5}$
$5d^{7}$
$4d^{7}$
$4d^{5}$

Explanation:

Technetium (Tc) is a transition metal with atomic number 43. Its full electron configuration is $[Kr] 4d^5 5s^2$, so the highest energy (last) portion involves the 4d orbital with 5 electrons.

Answer:

4d⁵