Question

Calculate the atomic mass of element "X", if it has 2 naturally occurring isotopes with the following masses and natural abundances: X-45 44. 8776 amu 32. 88% X-47 46. 9443 amu 67. 12%

Answer 1

46.2648

Step-by-step explanation:

Atomic mass describes the number of protons and neutrons in an atom.

Percent Abundance

Percent abundance is the percentage of atoms within a sample that have a specific mass number. The reason that different atoms within a sample would have different mass numbers is that they are different isotopes. For example, if the isotope Cl-35 has a percent abundance of 75%, then 75% of all Chlorine atoms within a sample will have a mass number of 35. Percent abundance refers to the likelihood of an isotope occurring in a natural sample. Percent abundance does not take into account artificial samples of elements.

Finding Atomic Mass

The atomic mass of an element is found through the mass of isotopes and their percent abundances. The formula for atomic mass is:

• m₁*p₁ + m₂*p₂

In this formula, the m is the mass of the isotope and p is the percent abundance. The percent abundance should be expressed as a decimal for all calculations. Now, plug in the values and solve.

• (44.8776 * 0.3288) + (46.9443 * 0.6712)

Rounded to 4 decimal places, this equals 46.2648. This means that the atomic mass of element "X" is 46.2648 amu.