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Haven
Haven asked in Science & MathematicsBiology · 1 decade ago

The sodium atom contains 11 electrons, 11 protons, and 12 neutrons. What is the mass number of sodium?

A. 11

B. 12

C. 23

4 Answers

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  • talr
    Lv 4
    1 decade ago
    Favorite Answer

    Mass number = number of nucleons (i.e. protons + neutrons), or in this case, 23.

    Source(s): http://en.wikipedia.org/wiki/Mass_number
  • ?
    5 years ago

    11 protons, 11 electrons and 12 neutrons. Why? Atomic mass is equal to the number of protons plus the number of neutrons. Atomic number is the number of protons present, and in every atom the number of protons and electrons MUST be equal! (Otherwise it's an ion!)

  • Goethe's Ghostwriter
    Lv 7
    1 decade ago

    Na: 23

  • bioteach
    Lv 5
    1 decade ago

    c. 23

    The mass number is the number of protons and neutrons in the nucleus.

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