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. **Determine Electron Configuration**: The electron configuration of Krypton can be determined by filling the electron shells according to the Aufbau principle. The shells are filled in the following order:
- K shell (1st shell): Can hold a maximum of 2 electrons.
- L shell (2nd shell): Can hold a maximum of 8 electrons.
- M shell (3rd shell): Can hold a maximum of 18 electrons.
- N shell (4th shell): Can hold a maximum of 32 electrons.

3. **Fill the Electron Shells**:
- K shell: 2 electrons
- L shell: 8 electrons
- M shell: 8 electrons
- N shell: 18 electrons (but since Krypton has only 36 electrons total, it will only have 8 electrons in the N shell)

4. **Count the Electrons in Each Shell**:
- K shell: 2 electrons
- L shell: 8 electrons
- M shell: 8 electrons
- N shell: 8 electrons (this is the valence shell)

5. **Identify the Penultimate Shell**: The penultimate shell is the shell before the outermost shell (valence shell). In this case, the penultimate shell is the M shell.

6. **Total Electrons in the Penultimate Shell**: The M shell has 8 electrons.

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

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