Tutopiya: Study Resources for IGCSE, IB, GCSE & A-Levels

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6 MCQs

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1
An atom's radius is about:
Answer & explanation
Correct: option B
Atom ≈ 10⁻¹⁰ m.
2
Charge of a proton:
Answer & explanation
Correct: option C
Proton +1; electron −1; neutron 0.
3
Compared with the atom, the nucleus is approximately:
Answer & explanation
Correct: option C
Atom 10⁻¹⁰ m ; nucleus 10⁻¹⁵ m → 10⁵ times smaller.
4
Mass of an electron compared with a proton:
Answer & explanation
Correct: option C
Electron ~ 1/2000 proton mass.
5
Electrons orbit:
Answer & explanation
Correct: option B
Discrete energy levels (shells).
6
When an electron drops to a lower energy level, it:
Answer & explanation
Correct: option B
Drop down → emit photon of EM radiation.