Question 28 of 40 The element thallium is 70% thallium 1-205 and 30% thallium 1-203 Calculate its relative atomic mass. Give your answer to 4 significant figures. Enter your answer as a number

## Step1:We are given that Thallium consists of Thallium-205 and Thallium-203.## Step2:The method to compute the relative atomic mass of an element is by using the natural abundances of its isotopes and their respective masses. Here, the relative atomic mass of Thallium can be calculated with the help of given percent abundance of Thallium-205 isotope and Thallium-203 isotope along with their atomic mass numbers.## Step3:We carry out this calculation using the following formula: ### **Relative atomic mass = \(\frac{({\%}_{abundance\_of\_isotope_1} \times {atomic\_mass\_of\_isotope_1}) + ({\%}_{abundance\_of\_isotope_2} \times {atomic\_mass\_of\_isotope_2})}{100}\)**## Step4:Substitution of our given values into the above formula results in the following calculation:### **Relative atomic mass = \(\frac{(70.0\% \times 205) + (30.0\% \times 203)}{100} = 204.6\)amu**