which element will form the ion with the largest ionic radius? b be li

Explanation:

Step1: Recall ionic - radius trend

Ionic radius increases as we move from right - to - left across a period for cations of the same charge.

Step2: Analyze the given elements

Li, Be, and B are in the same period (period 2). Li forms a + 1 cation ($Li^+$), Be forms a + 2 cation ($Be^{2 + }$), and B forms a + 3 cation ($B^{3+}$). All these cations have the same electron - configuration (isoelectronic with He).

Step3: Determine the ion with largest radius

The ion with the lowest positive charge will have the largest ionic radius among isoelectronic species. Since $Li^+$ has the lowest positive charge among $Li^+$, $Be^{2 + }$, and $B^{3+}$, it has the largest ionic radius.

Answer:

Li