CAPF AC 2017 PYQ with Answer — The mass number of an element is NOT changed when it emits

2017 · Q87

The mass number of an element is NOT changed when it emits

general-sciencechemistry

AAlpha and Beta radiations only
BAlpha and Gamma radiations only
CBeta and Gamma radiations only
DAlpha, Beta and Gamma radiations

Explanation

Alpha emission reduces the mass number by 4, while beta emission (a neutron converting to a proton) and gamma emission leave the mass number unchanged. Alpha particles, by contrast, carry away two protons and two neutrons, reducing the mass number by four. Hence the mass number is unchanged for beta and gamma radiations only, giving (C).