To determine the atomic mass of an element, you would take a _________ average of the isotopes that make up that element
weighted
To determine the atomic mass of an element, you would take a weighted average of the isotopes that make up that element. Here's how you can calculate it:
1. Identify the isotopes: Determine the different isotopes of the element along with their relative abundance. Isotopes are atoms of the same element that have different numbers of neutrons in their nuclei.
2. Find the atomic masses: Look up the atomic masses of each isotope. The atomic mass is usually given in atomic mass units (amu).
3. Calculate the weighted average: Multiply the atomic mass of each isotope by its relative abundance, expressed as a decimal. Then, add up the products of each isotope.
For example, let's calculate the atomic mass of chlorine (Cl) using its two isotopes, Cl-35 and Cl-37, with relative abundances of 75% and 25%, respectively. The atomic masses of Cl-35 and Cl-37 are 34.97 amu and 36.97 amu, respectively.
(34.97 amu * 0.75) + (36.97 amu * 0.25) = 35.38 amu
Therefore, the atomic mass of chlorine is approximately 35.38 amu.
Remember, the atomic mass given on the periodic table is often a decimal value because it represents the weighted average of all the naturally occurring isotopes of that element.