# The valence shell of the element X contains 2 electrons in a 5s subshell. Element X also has a partially filled 4d subshell. What type of element is X?

Element $X$ is a ${5}^{t h}$ period Transition element.
Since, $5 s$ orbital is fully filled, so the element $X$ lies in ${5}^{t h}$ principal shell, i.e. it lies in the ${5}^{t h}$ period.
Now, since the $4 d$ subshell is partially filled, so it is certain that the element $X$ is a ${5}^{t h}$period transition element.