On moving down a group of representative elements,both atomic and ionic radii increase with an increase in:

The statement$(s)$ that are correct about the species $O^{2-}$,$F^{-}$,$Na^{+}$,and $Mg^{2+}$.
$(A)$ All are isoelectronic
$(B)$ All have the same nuclear charge
$(C)$ $O^{2-}$ has the largest ionic radii
$(D)$ $Mg^{2+}$ has the smallest ionic radii
Choose the most appropriate answer from the options given below :

Which of the following arrangements represents the increasing order (smallest to largest) of ionic radii of the given species $O^{2-}, S^{2-}, N^{3-}, P^{3-}$?

Which one of the following has the largest ionic radius?

How is the atomic radius measured? Describe it.

The ionic radii $(\mathring{A})$ of $C^{4-}$ and $O^{2-}$ respectively are $2.60$ and $1.40$. The ionic radius of the isoelectronic ion $N^{3-}$ would be........$\mathring{A}$