Question

Identify the correct statements from the following :}
A. Heisenberg uncertainty principle is applicable to electrons.
B. The size of \(2p_x\) orbital is less than the size of \(3p_x\) orbital.
C. The energy of \(2s\) orbital of H atom is equal to the energy of \(2s\) orbital of Li.
D. The electronic configuration of Cr is \([Ar] 3d^5 4s^1\)

• A. A, B and C Only
• B. A, B and D Only
• C. B, C and D Only
• D. A, C and D Only

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The topic is Atomic Structure. We must evaluate four statements related to quantum mechanics, orbital properties, and electronic configurations to identify the correct set.
Step 2: Detailed Explanation:
Let's analyze each statement:
Statement A: Heisenberg uncertainty principle is applicable to electrons.
This is correct. The principle is a cornerstone of quantum mechanics and applies to all microscopic particles, with the electron being a primary example.
Statement B: The size of \(2p_x\) orbital is less than the size of \(3p_x\) orbital.
This is correct. The size of an atomic orbital is primarily determined by its principal quantum number (\(n\)). A higher \(n\) value means the orbital is larger and further from the nucleus. Thus, \(3p_x\) is larger than \(2p_x\).
Statement C: The energy of \(2s\) orbital of H atom is equal to the energy of \(2s\) orbital of Li.
This is incorrect. The energy of an orbital depends on the effective nuclear charge. Lithium (\(Z=3\)) has a much stronger nuclear pull on its electrons than Hydrogen (\(Z=1\)). This results in the \(2s\) orbital of Li having a significantly lower (more negative) energy than that of H.
Statement D: The electronic configuration of Cr is \([Ar] 3d^5 4s^1\).
This is correct. Chromium is a well-known exception to the Aufbau principle. The configuration \([Ar] 3d^5 4s^1\) is more stable than \([Ar] 3d^4 4s^2\) because it features half-filled \(d\) and \(s\) subshells.
Based on the analysis, statements A, B, and D are correct.
Step 3: Final Answer:
The correct statements are A, B and D Only.