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Atoms — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsAtoms1 Mark
MCQ
When an alpha particle is emitted from a radioactive source:
  • A
    Its atomic number increases by $4$
  • ✓
    Its atomic number decreases by $2$
  • C
    Its atomic number increases by $2$
  • D
    It atomic number decreases by $4$
✓

Answer

Correct option: B.
Its atomic number decreases by $2$

When an alpha particle is emitted from a radioactive source or substance, its atomic number decreases by $2$ and its atomic mass decreases by $4$, which is same as that of helium ion.

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