Question

for each atom in the table below, write down the subshell from which an electron would have to be removed to make a +1 cation, and the subshell to which an electron would have to be added to make a -1 anion.
the first row has been completed for you.

Explanation:

Ar

Step1: Determine subshell for +1 cation

Argon (Ar) has a full - shell electron configuration \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}\). To form a + 1 cation, we need to remove an electron from the outermost subshell. The outermost subshell is \(3p\).

Step2: Determine subshell for -1 anion

Since Ar has a full - shell configuration, adding an electron would go into the next available subshell. The next subshell after \(3p\) is \(4s\) (but according to the Aufbau principle, for forming an anion, we consider the subshell that can accept an electron. However, Ar is a noble gas and does not readily form an anion. But if we follow the pattern of electron addition for a hypothetical - 1 anion, based on electron - filling order, after \(3p\) (which is full), the next subshell is \(4s\). But in reality, for the sake of the problem (similar to the electron - removal/addition concept), if we assume the closest subshell that can conceptually take an electron (even though Ar is very stable), we can consider that there is no proper subshell for Ar to form a - 1 anion in a normal chemical sense. But if we follow the electron - shell order, we can say there is no valid subshell (or we can note that it's against the noble - gas stability). But if we force the answer based on subshell order, we can say \(4s\) (but it's a very forced answer as Ar does not form - 1 anion in normal chemistry).

K

Step1: Determine subshell for +1 cation

Potassium (K) has an electron configuration \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}\). The outermost electron is in the \(4s\) subshell. To form a + 1 cation (\(K^{+}\)), we remove the electron from the \(4s\) subshell.

Step2: Determine subshell for -1 anion

Potassium has a configuration \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}\). Adding an electron would go into the \(4p\) subshell (since \(4s\) is partially filled and after \(4s\) (for filling an extra electron for anion formation, following the Aufbau principle, after \(4s\) comes \(3d\) and then \(4p\). But for a - 1 anion of K (which is not common in normal chemistry as K is a metal and forms cations, but for the problem's sake), if we consider electron addition, the next available subshell (after \(4s\)) is \(4p\) (assuming we follow the subshell - filling order for anion formation conceptually).

Al

Step1: Determine subshell for +1 cation

Aluminum (Al) has an electron configuration \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{1}\). The outermost electron is in the \(3p\) subshell. To form a + 1 cation (\(Al^{+}\)), we remove an electron from the \(3p\) subshell.

Step2: Determine subshell for -1 anion

Aluminum has a configuration \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{1}\). Adding an electron would go into the \(3p\) subshell (since \(3p\) has \(1\) electron and can hold up to \(6\) electrons. For forming a - 1 anion (\(Al^{-}\)), we add an electron to the \(3p\) subshell.

Answer:

atom	subshell from which electron removed to form +1 cation	subshell to which electron added to form -1 anion
K	\(4s\)	\(4p\) (forced - based on subshell order, not a common chemical process)
Al	\(3p\)	\(3p\)