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Assertion : Among alkaline earth metals,...

Assertion : Among alkaline earth metals, Be predominantly forms covalent bond.
Reason : Be is smaller in size and hence has greater polarising power.

A

both assertion and reason are true and reason is the correct explanation of assertion.

B

both assertion and reason are true but reason in not the correct explanation of assertion.

C

assertion is true but reason is false.

D

both assertion and reason are false.

Text Solution

AI Generated Solution

The correct Answer is:
To solve the assertion and reason question, we will analyze both the assertion and the reason step by step. ### Step 1: Understand the Assertion The assertion states that "Among alkaline earth metals, Be predominantly forms covalent bonds." - **Explanation**: Beryllium (Be) is part of the alkaline earth metals group (Group 2) in the periodic table. Typically, alkaline earth metals tend to form ionic bonds due to their tendency to lose two electrons. However, beryllium is an exception because it forms covalent bonds more predominantly than the other alkaline earth metals. ### Step 2: Analyze the Reason The reason given is "Be is smaller in size and hence has greater polarizing power." - **Explanation**: The size of an atom affects its polarizing power, which is the ability of a cation to distort the electron cloud of an anion. Smaller cations have a higher charge density, which leads to greater polarizing power. Beryllium, being the smallest atom in the alkaline earth metals group, has the greatest polarizing power among them. ### Step 3: Relate Assertion and Reason Now we need to see if the reason supports the assertion. - **Explanation**: Since beryllium has the smallest size among the alkaline earth metals, it indeed has the greatest polarizing power. This high polarizing power allows beryllium to form covalent bonds with nonmetals, as it can effectively distort the electron clouds of the anions it interacts with. Therefore, the reason explains why beryllium predominantly forms covalent bonds. ### Conclusion Both the assertion and reason are true, and the reason correctly explains the assertion. ### Final Answer Both assertion and reason are true, and the reason is the correct explanation of the assertion. ---
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