Question

An unknown element X has the following isotopes: 126X (22.00%

Answer 1

Answer:

$m_X=128.44 a.m.u$

Explanation:

Hello there!

In this case, since the average atomic mass of an element, when given the atomic mass and the percent abundance of the naturally occurring isotopes is computed as shown below for this unknown element:

$m_X=126*0.22+128*0.34+130*0.44$

Whereas the atomic mass of each isotope is multiplied by the percent abundancy; we obtain:

$m_X=128.44 a.m.u$

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