Question

I am completely lost in chemistry. Everything the teacher says sounds like a different language to me and I am usually really good in the class. Can someone help me do this problem please?

An element "E" is present as 10E (The 10 is like an exponent to the left of the E) with a mass volume of 10.01 amu, and as 11E (again, like an exponent)with as mass value of 11.01 amu. The natural abundances of 10E and 11E are 19.78% and 80.22% respectively. What is the average atomic mass of the element? What is the element.

I don't even know where to start. The parentheses are my own explanation of what the numbers on the sheet actually looks like.

Please help!

Answer 1

₁₀E means the atomic mass is 10 for the unknown element, E. Same nomenclature for ₁₁E.

When you talked about atomic masses in class, I'm sure you heard that the atomic masses shown on the periodic table are the weighted averages of all the isotopes that occur naturally. So just take the weighted average (weighted just means use the percentages listed).
(10.01*0.1978) + (11.01*0.8022) ??
Check my thinking. Check for typos.

Answer 2

This answer has been bothering me all day and I just realized what I had done. I placed the numbers as subscripts instead of superscripts. They should have read as ¹⁰E and ¹¹E. Other than that the answer is ok.