Identify the correct order of innic radii of the following ions

Options

A. `Al^(3+) gt K^(+) gt Mg^(2+) gt Li^(+)`
B. `K^(+) gt Mg^(2+) gt Al^(3+) gt Li^(+)`
C. `K^(+) gt Li^(2+) gt Mg^(2+) gt Al^(3+) `
D. `K^(+) gt Mg^(2+) gt Li^(+) gt Al^(3+)`

Answer

C

Explanation

Ionic radii of alkali metal ion is larger than alkaline earth metals due to higher nuclear charge. On the other hand, on moving down the group ionic radii increases. Thus, correct order of ionic radii is
` K^(+) gt Li^(+) gt Mg^(2+) gt Al^(3+)`