1. A typical α-decay from a parent nucleusAZX may be indicated as :
Group of answer choices
AZX → (A−4)(Z − 2) Y+ 42He
AZX → (A+4)(Z+2) Y +22He
AZX → (A−4)Z Y +42He
AZX → (A−4)(Z+2) Y +42He
2. An element of atomic number 83 in a relatively higher energystate decays radioactively to an element of atomic number 84 withlower energy level. This must include
Group of answer choices
an α emission
a β emission
a γ emission
a β & γ emission
3. The half- life of radium-226 is 1.6 × 103 . If asample initially contains 3.0 × 1016 such nuclei, whatis the number of radioactive radium-226 nuclei remaining after 4.8× 103 years?
Group of answer choices
2.25 × 1012
3.75 × 1016
2.2 × 1016
3.75 × 1015
