In which 'd' electrons are zero?

Options

A. Th
B. Es
C. Lu
D. Am

Answer

To solve the question "In which 'd' electrons are zero?", we need to analyze the electronic configurations of the given elements: Thorium, Einsteinium, Lutetium, and Americium. We will determine the number of 'd' electrons for each element.

### Step-by-Step Solution:

1. **Identify the Atomic Numbers and Electronic Configurations:**
- **Thorium (Th)**: Atomic number 90
- Electronic Configuration: [Rn] 6d² 7s²
- **Einsteinium (Es)**: Atomic number 99
- Electronic Configuration: [Rn] 5f¹¹ 6d⁰ 7s²
- **Lutetium (Lu)**: Atomic number 71
- Electronic Configuration: [Xe] 4f¹⁴ 5d¹ 6s²
- **Americium (Am)**: Atomic number 95
- Electronic Configuration: [Rn] 5f⁷ 6d⁰ 7s²

2. **Count the 'd' Electrons for Each Element:**
- **Thorium**: Has 2 'd' electrons (6d²).
- **Einsteinium**: Has 0 'd' electrons (6d⁰).
- **Lutetium**: Has 1 'd' electron (5d¹).
- **Americium**: Has 0 'd' electrons (6d⁰).

3. **Determine Which Elements Have Zero 'd' Electrons:**
- From the analysis, we find that:
- Einsteinium has 0 'd' electrons.
- Americium has 0 'd' electrons.
- Therefore, the correct answers to the question are Einsteinium and Americium.

### Final Answer:
The elements in which 'd' electrons are zero are **Einsteinium (Es)** and **Americium (Am)**.

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