MCQ
A neutral atom has $12$ electrons and $13$ neutrons. Its mass number is :
  • A
    $12$
  • B
    $4$
  • C
    $13$
  • $25$

Answer

Correct option: D.
$25$
ass $=$ number of electrons/ protones $+$ number of neutrons
$= 12 + 13 = 25$

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