Total number of electrons present in the penultimate shell of an element with atomic number 36 is

Options

A. 18
B. 10
C. 8
D. 16

Answer

To find the total number of electrons present in the penultimate shell of an element with atomic number 36, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Element**: The element with atomic number 36 is Krypton (Kr).

2. **Understand Electron Shells**: The electron configuration of an atom describes how electrons are distributed among the various shells. The shells are designated as K, L, M, N, etc.

3. **Determine Electron Configuration**:
- The K shell can hold a maximum of 2 electrons.
- The L shell can hold a maximum of 8 electrons.
- The M shell can hold a maximum of 18 electrons.
- The N shell can hold a maximum of 32 electrons.

4. **Fill the Electron Shells**:
- K shell: 2 electrons
- L shell: 8 electrons
- M shell: 8 electrons
- N shell: 18 electrons
- Total: 2 + 8 + 8 + 18 = 36 electrons

5. **Identify the Penultimate Shell**: The penultimate shell is the second to last shell in the electron configuration. For Krypton (atomic number 36), the shells are filled as follows:
- K (2 electrons)
- L (8 electrons)
- M (8 electrons)
- N (18 electrons)

Here, the penultimate shell is the M shell.

6. **Count Electrons in the Penultimate Shell**: The M shell contains 8 electrons.

### Final Answer:
The total number of electrons present in the penultimate shell of an element with atomic number 36 is **8 electrons**.

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