The electronic configuration of transition element $X$ is $[Ar] 3d^5$,and its oxidation state is $+3$. What is its atomic number?

Which of the following alloys is used to construct marine condenser tubes of ships?

Which of the following transition metal cations has the maximum number of unpaired electrons?

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$. Assertion $(A)$: In aqueous solutions $Cr^{2+}$ is reducing while $Mn^{3+}$ is oxidising in nature.
Reason $(R)$: Extra stability to half-filled electronic configuration is observed than incompletely filled electronic configuration.
In the light of the above statement,choose the most appropriate answer from the options given below:

Which of the following metals exists in a liquid state during the summer season?

Which of the following pairs of elements cannot form an alloy?