NEET Exam

-Exam

1. Quantum Numbers + Orbitals – Asked every year
Q. The number of angular nodes and radial nodes in 4d orbital are respectively:
A) 2, 1
B) 1, 2
C) 2, 2
D) 1, 1

Answer: A
Trick: Angular nodes = l, Radial nodes = n-l-1. For 4d: n=4, l=2 → Angular=2, Radial=4-2-1=1

2. Electronic Configuration Exceptions – NEET fav
Q. The electronic configuration of Cu (Z=29) is
:
A) 3d⁹ 4s²
B) 3d¹⁰ 4s¹
C) 3d⁸ 4s² 4p¹
D) 4s¹ 4p⁶ 3d³

Answer: B
NEET Loves: Cr 3d⁵4s¹ and Cu 3d¹⁰4s¹ due to extra stability[Ar]

3. Bohr Model Numerical – Direct formula
Q. The energy of an electron in the second Bohr orbit of H-atom is:

A) -13.6 eV
B) -3.4 eV
C) -1.51 eV
D) -0.85 eV

Answer: B
Formula: Eₙ = -13.6/n² eV → -13.6/4 = -3.4 eV

4. de Broglie Wavelength – NEET 2023, 2024 pattern
Q. If the velocity of an electron is 1.6×10⁶ m/s, its de Broglie wavelength is: [h=6.6×10⁻³⁴ Js, mₑ=9.1×10⁻³¹ kg]

A) 4.55 Å
B) 2.28 Å
C) 9.1 Å
D) 1.14 Å

Answer: A
λ = h/mv = 6.6×10⁻³⁴ / (9.1×10⁻³¹ × 1.6×10⁶) = 4.55×10⁻¹⁰ m = 4.55 Å

5. Photoelectric Effect Concept – Theory + Graph
Q. In photoelectric effect, the stopping potential depends on:

A) Intensity of incident light
B) Frequency of incident light
C) Both A and B
D) Neither A nor B
Answer: B
NEET Trap: Intensity changes photo-current, not stopping potential/KE

6. Hydrogen Spectrum – Series identification
Q. The spectral line in hydrogen spectrum corresponding to n₁=2, n₂=4 belongs to:

A) Lyman series
B) Balmer series
C) Paschen series
D) Brackett series

Answer: B
Rule: n₁=2 → Balmer, n₁=1 → Lyman, n₁=3 → Paschen

7. Isoelectronic Species – 1 Q confirmed every year
Q. Which of the following is NOT isoelectronic with O²⁻?

A) F⁻
B) Ne
C) Na⁺
D) Mg²⁺

Answer: D
All have 10e⁻ except Mg²⁺ which has 12-2=10e⁻... wait Mg²⁺ is 10e⁻ too. Better example: N³⁻, O²⁻, F⁻, Ne, Na⁺, Mg²⁺, Al³⁺ all 10e⁻. NEET would give K⁺ with 18e⁻ as odd one.