The element having electronic configuration `[Kr] 4d^(10) 4f^(14) 5s^(2) 5p^(6) 5d^(2) 6s^(2)` belongs to

Options

A. s-block
B. p-block
C. d-block
D. f-block

Answer

To determine the block of the element with the given electronic configuration `[Kr] 4d^(10) 4f^(14) 5s^(2) 5p^(6) 5d^(2) 6s^(2)`, we can follow these steps:

### Step 1: Identify the electronic configuration
The electronic configuration provided is:
- `[Kr]` indicates that the element has the same electron configuration as Krypton, which accounts for 36 electrons.
- The remaining configuration is `4d^(10) 4f^(14) 5s^(2) 5p^(6) 5d^(2) 6s^(2)`.

### Step 2: Count the total number of electrons
To find the total number of electrons:
- From `[Kr]`: 36 electrons
- From `4d^(10)`: 10 electrons
- From `4f^(14)`: 14 electrons
- From `5s^(2)`: 2 electrons
- From `5p^(6)`: 6 electrons
- From `5d^(2)`: 2 electrons
- From `6s^(2)`: 2 electrons

Adding these together:
\[ 36 + 10 + 14 + 2 + 6 + 2 + 2 = 72 \]

Thus, the element has a total of 72 electrons.

### Step 3: Determine the last electron's position
The last electron in the configuration is found in the `5d^(2)` subshell.

### Step 4: Identify the block of the element
The position of the last electron determines the block of the element:
- If the last electron enters the `s` subshell, it belongs to the s-block.
- If it enters the `p` subshell, it belongs to the p-block.
- If it enters the `d` subshell, it belongs to the d-block.
- If it enters the `f` subshell, it belongs to the f-block.

Since the last electron is in the `5d` subshell, the element belongs to the **d-block**.

### Conclusion
The element with the electronic configuration `[Kr] 4d^(10) 4f^(14) 5s^(2) 5p^(6) 5d^(2) 6s^(2)` belongs to the **d-block**.

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