The electronic configuration of bivalent Europium and trivalent cerium respectively is: (Atomic Number: Xe = 54, Ce = 58, Eu = 63)

Options

A. `[Xe]4f^7`, `[Xe]4f^1`
B. `[Xe]4f^7 6s^2`, `[Xe]4f^1`
C. `[Xe]4f^7 6s^2, [Xe]4f^1 5d^1 6s^2`
D. `[Xe]4f^7, [Xe]4f^1 5d^1 6s^2`

Explanation

To determine the electronic configurations of bivalent Europium (Eu²⁺) and trivalent Cerium (Ce³⁺), we will follow these steps:

### Step 1: Determine the electronic configuration of neutral Europium (Eu)
- The atomic number of Europium (Eu) is 63.
- The electronic configuration of neutral Europium is:
\[ \text{Eu: } [Xe] 6s^2 4f^7 \]
Here, [Xe] represents the electron configuration of Xenon, which accounts for the first 54 electrons.

### Step 2: Determine the electronic configuration of bivalent Europium (Eu²⁺)
- To find the configuration of Eu²⁺, we need to remove 2 electrons from the neutral Europium configuration.
- The electrons are removed first from the outermost shell (6s) before removing from the f-orbital.
- Therefore, the electronic configuration of Eu²⁺ is:
\[ \text{Eu}^{2+}: [Xe] 4f^7 \]

### Step 3: Determine the electronic configuration of neutral Cerium (Ce)
- The atomic number of Cerium (Ce) is 58.
- The electronic configuration of neutral Cerium is:
\[ \text{Ce: } [Xe] 6s^2 4f^1 5d^1 \]
This configuration indicates that Cerium has one electron in the 4f subshell and one in the 5d subshell.

### Step 4: Determine the electronic configuration of trivalent Cerium (Ce³⁺)
- To find the configuration of Ce³⁺, we need to remove 3 electrons from the neutral Cerium configuration.
- The electrons are removed from the 5d and then from the 4f subshells.
- Therefore, the electronic configuration of Ce³⁺ is:
\[ \text{Ce}^{3+}: [Xe] 4f^0 \]

### Final Answer:
- The electronic configuration of bivalent Europium (Eu²⁺) is \([Xe] 4f^7\).
- The electronic configuration of trivalent Cerium (Ce³⁺) is \([Xe] 4f^0\).