Atomic Structure | First Year Chemistry Past Paper MCQs | mosaicbro.com

Atomic Structure | First Year Chemistry Past Paper MCQs

7 of 44 questions (Page 2 of 7)

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8 According to Bohr's atomic model, radius of second orbit of hydrogen atom is:
Correct Answer: B
Explanation: Radius = n² × 0.529 Å ⇒ 2² × 0.529 Å = 2.116 Å for n=2.
9 Lines of Paschen series are produced when electrons jump from higher orbits to ___ orbit.
Correct Answer: C
Explanation: Paschen series corresponds to transitions ending at n=3 (infrared region).
10 Negative charge on cathode rays was established by:
Correct Answer: C
Explanation: Millikan's oil-drop experiment quantified the electron's charge (e = -1.6 × 10⁻¹⁹ C).
11 An orbital which is spherical and symmetrical is:
Correct Answer: A
Explanation: s-orbitals are spherically symmetric (l=0).
12 Angstrom is the unit of:
Correct Answer: B
Explanation: 1 Å = 10⁻¹⁰ m, used for atomic-scale distances.
13 Mass of electron is:
Correct Answer: B
Explanation: Electron rest mass = 9.1095 × 10⁻³¹ kg.
14 Neutron was discovered by:
Correct Answer: A
Explanation: James Chadwick discovered neutrons in 1932 via alpha-particle bombardment of beryllium.
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