Question

3. Write down the formula for the following decays showing all of the decay products. Use X for the chemical symbol of nucleus that remains after the decay but show the Z and A of the nucleus using the standard notation.

3A. ²⁵₁₁Na decays by beta-minus emission:

3B. ^34₁₅P decays by beta-plus emission:

3C. ²¹⁰₈₄Po decays by alpha emission.

3D. ⁹⁰₃₈Sr decays by Beta-minus decay with a half-life of 29.1 years.

Answer 1

Q3A.

in beta -minus decay, a neutron is converted to a proton and the process creates an electron and an electron antineutrino.

so the complete equation is :

25Na11 ---> 25Mg 12 +electron + antinuetrino

Q3B.

in beta plus emission, a proton is converted to a neutron and the process creates a positron and an electron neutrino

34P15 --> 34Si14 + position + electron neutrino

Q3C:

in alpha emission, an atomic nucleus emits an alpha particle and decays into an atom with mass number lesser by 4 and atomic number lesser by 2.

210Po84 --> 206 Pb 82 + alpha particle

Q3D.

beta minus decay:

90 Sr 38 --> 90 Y 39 + electron +electron antineutrino