Question

Calculate the average atomic mass of an element if 95.00% of all the atoms have a mass of 31.972 amu, 0.76% has a mass of 32.971amu and 4.22% have a mass of 33.967amu. Identify the element. Record your answer with the atomic mass followed by the element. Example: 55.55amu, Ja

Answer 1

The average atomic mass of the element is 32.0573 amu, and by comparing this to values on the periodic table, the element is identified as sulfur (S).

Step-by-step explanation:

To calculate the average atomic mass of an element based on its isotopic composition, we multiply the mass of each isotope by its relative abundance (expressed as a decimal), and then sum these products. For the element in question with the given isotopic abundances and masses, the computation is as follows:

• Mass of isotope 1: 31.972 amu × 0.9500 = 30.3734
• Mass of isotope 2: 32.971 amu × 0.0076 = 0.2504
• Mass of isotope 3: 33.967 amu × 0.0422 = 1.4335

Adding these together, 30.3734 + 0.2504 + 1.4335 = 32.0573 amu. Therefore, the average atomic mass of the element is 32.0573 amu.

The element can be identified by comparing the calculated average atomic mass with known values on the periodic table. The value 32.0573 amu closely matches the atomic mass of sulfur (S), which is approximately 32.07 amu. Thus, the element is sulfur (S).