Which one of the following sets of ions represents a collection of isoelectronic species?

Which of the following statements is/are correct?

Which of the following statements is incorrect?

State whether the following statements are true or false:
$(i)$ As the atomic number increases in a period,the nuclear charge increases,therefore the ionization enthalpy increases.
$(ii)$ As the metallic character of elements increases,the atomic radius generally increases.
$(iii)$ $Mn$ $(Z = 25)$ is a transition element. Although it is a $3d$-orbital element,its position in the periodic table is in the $4^{th}$ period.

Which element from the following exhibits a diagonal relationship with $Mg$?

An element of atomic weight $40$ has $2, 8, 8, 2$ as the electronic configuration. Which one of the following statements regarding this element is not correct?