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Assertion (A): Chromium is an actinoid. ...

Assertion (A): Chromium is an actinoid.
Reason (R): In Chromium, 3d orbitals are filled.

A

Both A and Rare true and R is the correct explanation of A.

B

Both A and R are true but R is NOT the correct explanation of A.

C

A is true but R is false.

D

A is false and R is True

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question regarding the assertion and reason, we will analyze both statements separately and determine their validity. ### Step 1: Analyze the Assertion (A) **Assertion (A): Chromium is an actinoid.** - **Explanation**: Chromium (Cr) is a chemical element with the atomic number 24. It belongs to the d-block of the periodic table, specifically the transition metals. The actinoids are a series of 15 elements from actinium (atomic number 89) to lawrencium (atomic number 103), which are located in the f-block of the periodic table. - **Conclusion**: Therefore, the assertion that chromium is an actinoid is **false**. ### Step 2: Analyze the Reason (R) **Reason (R): In Chromium, 3d orbitals are filled.** - **Explanation**: The electronic configuration of chromium is [Ar] 3d^5 4s^1. This means that in chromium, the 3d orbitals are not completely filled; instead, they contain 5 electrons, while the 4s orbital has 1 electron. Thus, the statement that "in chromium, 3d orbitals are filled" is misleading because they are not filled to capacity (which would require 10 electrons). - **Conclusion**: Therefore, the reason that "in chromium, 3d orbitals are filled" is **false**. ### Final Conclusion: - Since the assertion is false and the reason is also false, we conclude that both statements are incorrect. ### Answer: - The correct answer is that both the assertion and reason are false. ---
To solve the question regarding the assertion and reason, we will analyze both statements separately and determine their validity. ### Step 1: Analyze the Assertion (A) **Assertion (A): Chromium is an actinoid.** - **Explanation**: Chromium (Cr) is a chemical element with the atomic number 24. It belongs to the d-block of the periodic table, specifically the transition metals. The actinoids are a series of 15 elements from actinium (atomic number 89) to lawrencium (atomic number 103), which are located in the f-block of the periodic table. - **Conclusion**: Therefore, the assertion that chromium is an actinoid is **false**. ...
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