Question

1. use the periodic table to write the correct answer. what is the isotopic notation for the isotope krypton - 84? o kr³⁶₈₄ o ³⁶₈₄kr o kr⁸⁴₃₆ o ⁸⁴₃₆kr

Explanation:

Step1: Recall isotopic notation rules

Isotopic notation is $\ce{^{A}_{Z}X}$, where $A$ is the mass - number and $Z$ is the atomic number, and $X$ is the chemical symbol.

Step2: Find krypton's atomic number

From the periodic table, the atomic number of krypton ($Kr$) is 36.

Step3: Identify the mass - number

For krypton - 84, the mass - number $A = 84$.

Step4: Write the isotopic notation

The isotopic notation is $\ce{^{84}_{36}Kr}$.

Answer:

$84_{36}\text{Kr}$ (the last option in the multiple - choice list)