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Atomic Number and Mass Number MCQs

Practice Atomic Number and Mass Number multiple-choice questions from Structure of the Atom (Class 9 Science) - tap an answer for instant feedback and a step-by-step solution. Practice the full set free on the RankByte app.

Atomic Number and Mass NumberQuiz - Solve & Score

  1. Q1. A school science museum prints a card for sodium reading Z = 11 and A = 23; how many neutrons sit packed inside one nucleus?

    • A.11
    • B.34
    • C.23
    • D.12

    Answer: D. 12

    Number of neutrons = mass number - atomic number = A - Z = 23 - 11 = 12.

  2. Q2. While moulding a clay model of chlorine (atomic number 17, mass number 35), a learner asks how many neutron beads belong in the core; what is the count?

    • A.17
    • B.35
    • C.18
    • D.52

    Answer: C. 18

    Number of neutrons = mass number - atomic number = A - Z = 35 - 17 = 18.

  3. Q3. A planetarium exhibit lists calcium with 20 protons and a nucleon total of 40; what number of those nucleons are neutrons?

    • A.60
    • B.21
    • C.20
    • D.40

    Answer: C. 20

    Number of neutrons = mass number - atomic number = A - Z = 40 - 20 = 20.

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