Question

1. look at boron. it has two possible isotopes. based on the average atomic mass on the periodic table (10.81), which isotope is most abundant in nature? justify your answer.

Explanation:

Step1: Identify boron isotopes

Boron has two isotopes: $^{10}B$ with mass number 10 and $^{11}B$ with mass number 11.

Step2: Analyze average atomic mass

The average atomic mass of boron is 10.81. It is closer to 11 than to 10.

Step3: Determine abundant isotope

The isotope whose mass number is closer to the average atomic mass is more abundant. So, $^{11}B$ is more abundant in nature.

Answer:

The $^{11}B$ isotope is most abundant in nature because the average atomic mass of boron (10.81) is closer to the mass - number of $^{11}B$ (11) than to the mass - number of $^{10}B$ (10).