In which of the following pairs is the difference between the covalent radii of the two metals maximum?

Between $Al$ and $Al^{3+}$,which has a smaller radius and why?

Which of the following is arranged in decreasing order of size?

Given below are two statements:
Statement $I$: The metallic radius of $Na$ is $1.86 \ \mathring{A}$ and the ionic radius of $Na^{+}$ is lesser than $1.86 \ \mathring{A}$.
Statement $II$: Ions are always smaller in size than the corresponding elements.
In the light of the above statements,choose the correct answer from the options given below:

Which of the following represents the correct order of ionic radii?

The atomic radii $(pm)$ of $Al, Si, N$ and $F$ respectively are: