How many unpaired electrons are there in the electronic structure for `Cu^+` ion?

Explanation

To determine the number of unpaired electrons in the electronic structure of the `Cu^+` ion, we can follow these steps:

### Step 1: Identify the atomic number of Copper (Cu)
The atomic number of copper (Cu) is 29. This means that a neutral copper atom has 29 electrons.

**Hint:** Remember that the atomic number corresponds to the number of protons and, in a neutral atom, also the number of electrons.

### Step 2: Write the electronic configuration of neutral Copper (Cu)
The electronic configuration for a neutral copper atom is:
- 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s¹

This can also be represented in shorthand notation as:
- [Ar] 3d¹⁰ 4s¹

**Hint:** Use the noble gas shorthand to simplify writing the electronic configuration.

### Step 3: Determine the configuration for `Cu^+`
The `Cu^+` ion indicates that copper has lost one electron. The electron is removed from the outermost shell, which is the 4s orbital in this case. Therefore, the electronic configuration for `Cu^+` becomes:
- [Ar] 3d¹⁰ 4s⁰

**Hint:** When forming cations, electrons are typically removed from the highest energy level first.

### Step 4: Analyze the electronic configuration of `Cu^+`
In the configuration [Ar] 3d¹⁰ 4s⁰:
- The 3d subshell has 10 electrons, which means it is completely filled.
- The 4s subshell has 0 electrons.

**Hint:** A filled subshell (like 3d¹⁰) means that there are no unpaired electrons in that subshell.

### Step 5: Count the unpaired electrons
Since both the 3d subshell is completely filled and the 4s subshell is empty, there are no unpaired electrons in the `Cu^+` ion.

**Final Answer:** The number of unpaired electrons in the `Cu^+` ion is **0**.

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