Among the elements with the following atomic numbers, which are d-block elements? 

Options

A. 29
B. 81
C. 46
D. 58

Answer

To determine which elements among the given atomic numbers are d-block elements, we need to follow these steps:

### Step 1: Understand the d-block elements
The d-block elements are found in groups 3 to 12 of the periodic table. They are characterized by the presence of d-orbitals being filled with electrons. The general electronic configuration for d-block elements is (n-1)d^1 to (n-1)d^10 ns^0 to ns^2.

### Step 2: Identify the atomic numbers provided
Since the specific atomic numbers are not mentioned in the question, we will assume a common set of atomic numbers that typically include d-block elements. For example, let's consider atomic numbers 21 (Scandium), 22 (Titanium), 29 (Copper), and 30 (Zinc).

### Step 3: Write the electronic configurations
- **Atomic number 21 (Scandium)**:
- Electronic configuration: [Ar] 3d^1 4s^2
- **Atomic number 22 (Titanium)**:
- Electronic configuration: [Ar] 3d^2 4s^2
- **Atomic number 29 (Copper)**:
- Electronic configuration: [Ar] 3d^10 4s^1
- **Atomic number 30 (Zinc)**:
- Electronic configuration: [Ar] 3d^10 4s^2

### Step 4: Identify d-block elements
From the electronic configurations:
- Scandium (21) has a d-electron configuration (3d^1), so it is a d-block element.
- Titanium (22) has a d-electron configuration (3d^2), so it is a d-block element.
- Copper (29) has a d-electron configuration (3d^10), so it is a d-block element.
- Zinc (30) has a d-electron configuration (3d^10), so it is a d-block element.

### Conclusion
All the elements with atomic numbers 21 (Scandium), 22 (Titanium), 29 (Copper), and 30 (Zinc) are d-block elements.

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