Assertion:- In MgO electrovalency of Mg is 2.
Reason :- Mg shares two electrons with oxygen.

Options

A. If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.
B. If both Assertion & Reason are True but Reason is not a correct explanation of the Assertion.
C. If Assertion is True, but the Reason is False.
D. If both Assertion & Reason are false

Answer

To solve the question, we will analyze both the assertion and the reason step by step.

### Step 1: Understand the Assertion
The assertion states that "In MgO, the electrovalency of Mg is 2."

**Explanation**:
- Electrovalency refers to the number of electrons an atom can lose or gain to achieve a stable electronic configuration.
- Magnesium (Mg) has an atomic number of 12, which means it has 12 electrons. Its electronic configuration is 1s² 2s² 2p⁶ 3s².
- In the outermost shell (the third shell), magnesium has 2 electrons (3s²).
- To achieve a stable electronic configuration like that of the nearest noble gas (Neon), magnesium loses these 2 electrons, forming a Mg²⁺ ion.

**Conclusion**: The assertion is true.

### Step 2: Understand the Reason
The reason states that "Mg shares two electrons with oxygen."

**Explanation**:
- In the formation of magnesium oxide (MgO), oxygen (O) has an atomic number of 8 and an electronic configuration of 1s² 2s² 2p⁴.
- Oxygen needs 2 additional electrons to complete its octet (8 electrons in the outer shell).
- In the reaction, magnesium loses 2 electrons, and oxygen gains those 2 electrons.
- This process is called ionic bonding, where magnesium transfers its electrons to oxygen rather than sharing them.

**Conclusion**: The reason is false.

### Step 3: Final Evaluation
- The assertion is true: "In MgO, the electrovalency of Mg is 2."
- The reason is false: "Mg shares two electrons with oxygen."

### Final Answer
The correct option is: **Assertion is true, but the reason is false.**

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