Explanation: To get the average atomic mass, we will follow these steps: 1- multiply the atomic mass of each isotope by its percentage of abundance 2- add the products
We are given that: 1- The first isotope has an atomic mass of 45.95293 and percentage of abundance equals 72% 2- The second isotope has an atomic mass of 47.94795 and percentage of abundance equals 11% 3- The third isotope has an atomic mass of 49.94479 and percentage of abundance equals 17%
Following the mentioned steps, we can get the average atomic mass as follows: average atomic mass = (45.95293)(0.72)+(47.94795)(0.11)+(49.94479)(0.17) = 46.8509984 amu
Atoms with the same number of protons but different numbers of neutrons are called isotopes. Because the number of neutrons can vary for a given element, the mass numbers of different atoms of an element may also vary. For example, some helium atoms have three neutrons instead of two (these are called isotopes and are discussed in detail later on)
