The element which shows only one oxidation state other than its elemental form is:

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A)$: The first ionization enthalpy of $3d$ series elements is more than that of group $2$ metals.
Reason $(R)$: In $3d$ series of elements,successive filling of $d$-orbitals takes place.
In the light of the above statements,choose the correct answer from the options given below:

Which of the following elements is found in the human body?

Which elements were named by the following?
$(i)$ Lawrence Berkeley Laboratory
$(ii)$ Seaborg's group

An element having the electronic configuration $[Ar]3d^24s^2$ belongs to

Transition metals are often paramagnetic owing to