Calculate the atomic mass of element "X" if it has 2 naturally occurring isotopes with the following masses and natural abundances. X−107 106.90509 amu 51.84%X−109 108.90476 amu 48.46%

Using my (not very precise) periodic table, I get the mass of Ag as 107.87

Explanation:

This must be a combination of these two isotopes. So the % of the other isotope must be 48.16%.

To work with these percentages in an equation I'll use them as decimals.

So now I can start putting them into an equation:

107.87  =  ( 106.905 ⋅ 0.5184 )  +  ( x ⋅ 0.4816 )  

Because both of the isotope masses, multiplied by their percentage, would give us the overall average mass.

107.87  =  55.419552  ⋅  (  x  ⋅  0.4816 )  

Worked out the brackets that we can work out, and then rearrange to give:

107.87  −  55.419552  =  (  x  ⋅  0.4816  )

Again rearrange:

52.450448 =  (  x  ⋅  0.4816  )  

And final rearranging:

x  =  52.450448  - 0.4816

x

=

108.909

(using same sig figs as given in question)

You probably want to work through that again using your periodic table value for Ag.

so what is the problem with your lab report and whats the subject of the lab report? i will you