Which nuclear decay alters atomic number but not mass?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. Beta Decay.
In Beta Decay, a neutron in the nucleus transforms into a proton while emitting an electron (beta particle). This process increases the atomic number by 1, effectively changing the element, but the mass number remains the same because the total number of nucleons (protons + neutrons) does not change. It is a fundamental process that allows unstable nuclei to move toward a more stable proton-neutron ratio.
Other Options:
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Alpha Decay: Emits a helium nucleus, reducing the atomic number by 2 and the mass number by 4.
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Gamma Decay: Emits high-energy photons; it changes neither the atomic number nor the mass number.
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Fission: A heavy nucleus splits into smaller nuclei, significantly altering both mass and atomic numbers.