Question

1. suppose each of these isotopes emits a beta particle. give the isotope name and symbol for the isotope that is produced. place a checkmark next to the symbol for isotopes that are stable. (consult the isotope graph on page 72 of lesson 14: isotopia.) a. potassium - 42 b. iodine - 131 c. iron - 52 d. sodium - 24

Explanation:

Step1: Recall beta - decay equation

In beta - decay, a neutron in the nucleus is converted into a proton and an electron (beta particle). The general equation is $_{Z}^{A}X
ightarrow_{Z + 1}^{A}Y+_{- 1}^{0}e$.

Step2: Analyze potassium - 42 decay

Potassium has atomic number $Z = 19$. For $_{19}^{42}K$, after beta - decay, the new element has $Z=19 + 1=20$, which is calcium. The symbol is $_{20}^{42}Ca$. According to the isotope graph (not shown here, but in general knowledge), calcium - 42 is not stable.

Step3: Analyze iodine - 131 decay

Iodine has atomic number $Z = 53$. For $_{53}^{131}I$, after beta - decay, the new element has $Z = 53+1 = 54$, which is xenon. The symbol is $_{54}^{131}Xe$. Xenon - 131 is stable.

Step4: Analyze iron - 52 decay

Iron has atomic number $Z = 26$. For $_{26}^{52}Fe$, after beta - decay, the new element has $Z=26 + 1=27$, which is cobalt. The symbol is $_{27}^{52}Co$. Cobalt - 52 is not stable.

Step5: Analyze sodium - 24 decay

Sodium has atomic number $Z = 11$. For $_{11}^{24}Na$, after beta - decay, the new element has $Z=11 + 1=12$, which is magnesium. The symbol is $_{12}^{24}Mg$. Magnesium - 24 is stable.

Answer:

a. Calcium - 42, $_{20}^{42}Ca$
b. Xenon - 131, $_{54}^{131}Xe$ (✓)
c. Cobalt - 52, $_{27}^{52}Co$
d. Magnesium - 24, $_{12}^{24}Mg$ (✓)