Question

question 11 (3 points)
218 84 po → 0 -1 e⁻ +
word bank:
218 bi at 85 83 219
blank 1:
blank 2:
blank 3:

Explanation:

Step1: Balance mass - number

In a nuclear - decay equation, the sum of mass - numbers on the left side must equal the sum of mass - numbers on the right side. The mass - number of $^{218}_{84}Po$ is 218 and the mass - number of the electron $^{0}_{ - 1}e$ is 0. So the mass - number of the daughter nucleus is 218.

Step2: Balance atomic - number

The sum of atomic numbers on the left side must equal the sum of atomic numbers on the right side. The atomic number of $^{218}_{84}Po$ is 84 and the atomic number of the electron $^{0}_{ - 1}e$ is - 1. Let the atomic number of the daughter nucleus be $Z$. Then $84= - 1+Z$, so $Z = 85$.

Step3: Identify the element

The element with atomic number 85 is astatine, symbol At.

Answer:

Blank 1: 218
Blank 2: At
Blank 3: 85