Multi Electron Atoms

Step 1: Recall the trend of electron affinity in the periodic table.

Electron affinity generally increases across a period (left to right) and decreases down a group (top to bottom). However, there is an exception among halogens: fluorine ( ) has a slightly lower electron affinity than chlorine ( ) due to its small size, which causes significant repulsion between added electrons and existing electrons in the compact orbital.

Among the halogens, chlorine ( ) has the highest electron affinity because it can more effectively attract and hold an additional electron compared to fluorine ( ). Bromine ( ) and iodine ( ) have lower electron affinities due to their larger sizes.

Final Answer: The halogen with the highest electron affinity is , which corresponds to option .

Step 1: Recall the formula for the maximum number of electrons in a shell.

The maximum number of electrons that can be accommodated in a shell is given by:

where is the principal quantum number of the shell.

Step 2: Identify the principal quantum number of the L shell.

The L shell corresponds to . Substituting into the formula:

Final Answer: The maximum number of electrons in the L shell is , which corresponds to option .