The atomic number of an element ‘y ’ is 20. The electronic configuration of the ion having inert gas configuration is

Options

A. 2,8,10
B. 2,18
C. 2,10,8
D. 2,8,8

Answer

To find the electronic configuration of the ion of element 'y' (which has an atomic number of 20) that has an inert gas configuration, we can follow these steps:

### Step 1: Identify the element
The atomic number of 20 corresponds to the element Calcium (Ca).

### Step 2: Write the electronic configuration of Calcium
The electronic configuration of Calcium (Ca) can be determined based on its atomic number:
- Calcium has 20 electrons, and its electronic configuration is:
\[ 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 \]
This can be simplified to:
\[ [Ar] 4s^2 \]
where [Ar] represents the electron configuration of Argon, which is the nearest noble gas.

### Step 3: Determine the ion with inert gas configuration
To achieve an inert gas configuration, Calcium (Ca) will lose 2 electrons, as it is in Group 2 of the periodic table. When it loses these two electrons, it becomes a Calcium ion (Ca²⁺).

### Step 4: Write the electronic configuration of the Ca²⁺ ion
After losing 2 electrons from the outermost shell (4s²), the electronic configuration of the Ca²⁺ ion becomes:
\[ [Ar] \]
This indicates that the ion now has the same electronic configuration as Argon, which is an inert gas.

### Final Answer
The electronic configuration of the ion having inert gas configuration (Ca²⁺) is:
\[ [Ar] \]

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