Selected MCQ

Current Question
Which quantum number set is impossible for an electron in an atom?
  • A. (n=3,\ l=2,\ m_l=1)
  • B. (n=2,\ l=2,\ m_l=0)
  • C. (n=4,\ l=1,\ m_l=-1)
  • D. (n=1,\ l=0,\ m_l=0)
Correct Answer: B
Explanation:
For principal quantum number (n), the azimuthal quantum number must satisfy (0 \le l \le n-1).
Related Question 1
Which quantum number determines orbital shape?
  • A. Principal
  • B. Azimuthal
  • C. Magnetic
  • D. Spin
Correct Answer: B
Explanation:
Azimuthal quantum number defines orbital geometry.
Related Question 2
Which bond involves delocalized electrons?
  • A. Ionic
  • B. Covalent
  • C. Metallic
  • D. Hydrogen
Correct Answer: C
Explanation:
Metallic bonding has electron sea.
Related Question 3
Which species is isoelectronic with Ne?
  • A. Na⁺
  • B. Mg²⁺
  • C. F⁻
  • D. All of the above
Correct Answer: D
Explanation:
All have 10 electrons like neon.
Related Question 4
In a Hilbert space formulation of quantum mechanics, physical states are represented by:
  • A. Real numbers
  • B. Vectors up to a global phase
  • C. Scalars only
  • D. Matrices only
Correct Answer: B
Explanation:
States are rays in Hilbert space, invariant under global phase.
Related Question 5
Which reaction releases electrons?
  • A. Reduction
  • B. Oxidation
  • C. Neutralization
  • D. Precipitation
Correct Answer: B
Explanation:
Oxidation is loss of electrons.