draw an outer electron box diagram for a cu²⁺ cation.

Explanation:

Step1: Determine copper's atomic number

Copper (Cu) has an atomic number of 29. So its neutral - atom electron configuration is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{1}$.

Step2: Consider the $Cu^{2 + }$ ion

A $Cu^{2 + }$ ion has lost 2 electrons. It first loses the 4s electron and then one 3d electron. So the electron configuration of $Cu^{2 + }$ is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{9}$.

Step3: Draw the outer - electron box diagram

The outer - shell electrons for $Cu^{2 + }$ are in the 3d sub - shell. The 3d sub - shell has 5 orbitals. For $3d^{9}$, we fill the 5 orbitals according to Hund's rule. Four of the orbitals will have 2 electrons (paired) and one orbital will have 1 electron.

3d
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Answer:

3d
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