Question

Justin discovered an unknown element with the following natural abundances and isotopic masses: 80.92% abundance with 19.99 amu, 0.260% abundance with 20.99 amu, 18.82% abundance with 21.99 amu.

Calculate the average atomic mass of this element. (Round according to significant figures)

Answer 1

To calculate the average atomic mass of an element with multiple isotopes, multiply the abundance of each isotope by its mass and then add up all the results.

Step-by-step explanation:

To calculate the average atomic mass of an element with multiple isotopes, you need to multiply the abundance of each isotope by its mass and then add up all the results. In this case, the element has three isotopes with respective abundances and masses. Multiply the abundance of each isotope by its mass and then add up the products. For example, (0.8092 * 19.99) + (0.0026 * 20.99) + (0.1882 * 21.99) = 16.1676 + 0.054374 + 4.153318 = 20.375292 amu. Therefore, the average atomic mass of this element is 20.375 amu.